SO Substitutions in 9.2

We are in the middle of our user testing for the 9,2 upgrade and are finding that in an EDI-generated sales order, users are not allowed to cancel lines manually.  It seems that in 9.0, there was a bug that allowed them to cancel EDI lines.

The issue is with substitutions.  Our business needs to substitute items on edi orders and now are not able to.   Is anyone using substitutions in 9.2 in EDI generated sales order lines?  If so, how are you handling this business requirement?