Hello,
(writing this the second time because I got timed out grrrr
If you mean the forms already exist in an sharepoint library, then you would
need to write some sort of library event or process that would automatically
rename the files based on some sequencing algorithm you write. Check
"Sharepoint library events" for information on writing the former, the latter
would be Sharepoint object model.
If you mean the forms would be new ones saved to the library, then you may
have to write code to submit based on your own requirements. For example,
create your own submit function that would automatically set the name of the
form based on some sequential number algorithm as above. This could be based
on the date/time, number supplied by database, even the count of items in the
list (though this doesn't work if you are deleting items from the same list!)
HTH
Gavin.