Do you want the values in the value list sorted or the records in the portal sorted?
If you want to sort the values in the value list by ProductID, you can open the value list in Manage | value lists and change the "sort values using" option from "second field" to "first field".
If you want the portal records to be sorted, enter layout mode and double click the portal. This opens portal setup where you have an option for specifiying a sort order for the records in the portal.
Thank you for the help!!!!