diff --git a/src/main/java/org/orph2020/pst/apiimpl/rest/ProposalDocumentStore.java b/src/main/java/org/orph2020/pst/apiimpl/rest/ProposalDocumentStore.java
index 12da420..5cdf88f 100644
--- a/src/main/java/org/orph2020/pst/apiimpl/rest/ProposalDocumentStore.java
+++ b/src/main/java/org/orph2020/pst/apiimpl/rest/ProposalDocumentStore.java
@@ -3,6 +3,7 @@
 import jakarta.enterprise.context.RequestScoped;
 import org.apache.commons.io.FileUtils;
 import org.eclipse.microprofile.config.inject.ConfigProperty;
+import org.ivoa.dm.proposal.prop.SupportingDocument;
 
 import java.io.File;
 import java.io.FileWriter;
@@ -11,10 +12,15 @@
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.Arrays;
+import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+/**
+ *  This is a convenience class bean to help with file I/O and bookkeeping for the document store
+ *  of individual proposals
+ */
 @RequestScoped
 public class ProposalDocumentStore {
 
@@ -61,14 +67,22 @@ public void removeStorePath(String proposalDirectory) throws IOException {
     }
 
     /**
-     * Copies the contents of directory 'source' to the directory 'destination', this includes
-     * subdirectories and files
-     * @param source a string representing the source directory
-     * @param destination a string representing the destination directory
+     * Copies the contents of directory 'source' to the directory 'destination', this includes subdirectories
+     * and files (intention is that 'source' and 'destination' are unique identifiers for proposals)
+     * @param source a string representing the source directory or path (not including the store root)
+     * @param destination a string representing the destination directory or path (not including the store root)
+     * @param supportingDocuments list of supporting documents from the CLONED proposal to update
+     *                            their 'locations' to use the 'destination' path - can be empty
      * @throws IOException if copy operation fails
      */
-    public void copyStore(String source, String destination) throws IOException {
+    public void copyStore(String source, String destination, List<SupportingDocument> supportingDocuments)
+            throws IOException {
         FileUtils.copyDirectory(fetchFile(source), fetchFile(destination));
+        supportingDocuments.forEach(s ->
+            s.setLocation(s.getLocation().replace(
+                    "proposals/" + source,"proposals/" + destination
+            ))
+        );
     }
 
 
diff --git a/src/main/java/org/orph2020/pst/apiimpl/rest/ProposalResource.java b/src/main/java/org/orph2020/pst/apiimpl/rest/ProposalResource.java
index c33b411..1a1e1fe 100644
--- a/src/main/java/org/orph2020/pst/apiimpl/rest/ProposalResource.java
+++ b/src/main/java/org/orph2020/pst/apiimpl/rest/ProposalResource.java
@@ -207,19 +207,16 @@ public ObservingProposal cloneObservingProposal(@PathParam("proposalCode") long
 
         //copy the document store for the new, cloned proposal
         try {
-            proposalDocumentStore.copyStore(prop.getId().toString(), clonedProp.getId().toString());
+            proposalDocumentStore.copyStore(
+                    prop.getId().toString(),
+                    clonedProp.getId().toString(),
+                    clonedProp.getSupportingDocuments()
+            );
         }
         catch (IOException e) {
             throw new WebApplicationException(e);
         }
 
-        //clonedProp now has SupportingDocuments with 'locations' indicating the original proposal,
-        //these need to be updated with the clone's id.
-        clonedProp.getSupportingDocuments().forEach(
-                s -> s.setLocation(s.getLocation().replace(
-                        "proposals/" + prop.getId(),"proposals/" + clonedProp.getId()))
-        );
-
         return clonedProp;
     }
 
diff --git a/src/main/java/org/orph2020/pst/apiimpl/rest/SubmittedProposalResource.java b/src/main/java/org/orph2020/pst/apiimpl/rest/SubmittedProposalResource.java
index 957d511..9f81e86 100644
--- a/src/main/java/org/orph2020/pst/apiimpl/rest/SubmittedProposalResource.java
+++ b/src/main/java/org/orph2020/pst/apiimpl/rest/SubmittedProposalResource.java
@@ -1,6 +1,7 @@
 package org.orph2020.pst.apiimpl.rest;
 
 
+import jakarta.inject.Inject;
 import jakarta.persistence.Query;
 import jakarta.persistence.TypedQuery;
 import jakarta.transaction.Transactional;
@@ -18,6 +19,7 @@
 import org.orph2020.pst.common.json.ObjectIdentifier;
 import org.orph2020.pst.common.json.ProposalSynopsis;
 
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
@@ -27,6 +29,9 @@
 @Produces(MediaType.APPLICATION_JSON)
 public class SubmittedProposalResource extends ObjectResourceBase{
 
+    @Inject
+    ProposalDocumentStore proposalDocumentStore;
+
     @GET
     @Operation(summary = "get the identifiers for the SubmittedProposals in the ProposalCycle")
     public List<ObjectIdentifier> getSubmittedProposals(
@@ -123,6 +128,21 @@ public ProposalSynopsis submitProposal(@PathParam("cycleCode") long cycleId, Sub
         submittedProposal.updateClonedReferences();
         em.persist(submittedProposal);
         submittedProposal.addToRelatedProposals(new RelatedProposal(proposal));
+
+        //**** clone the document store of the original proposal ****
+        //in essence creates a snapshot of the documents at the point of submission
+        try {
+            proposalDocumentStore.copyStore(
+                    proposal.getId().toString(),
+                    submittedProposal.getId().toString(),
+                    submittedProposal.getSupportingDocuments()
+            );
+        } catch (IOException e) {
+            // if we can't copy the store then we need to rollback
+            throw new WebApplicationException(e);
+        }
+        //************************************************************
+
         cycle.addToSubmittedProposals(submittedProposal);
         em.merge(cycle);