Here's what we usually do - add a field to the form that has a unique id of some kind - like user name and now(), for example - set the field on form load if it is blank, that way you know you have a stable, unique ID. Promote that field to the form library. Add a query to the library that includes this new column and the ID column - don't run on load. Then, when you submit the form, you can set the query field to the unique ID in this secondary question, and then run the query to get the ID back....
Hilary Stoupa
