Create Confirmation button grayed out for amended SRM Purchase Orders

Folks,

Is there some note or something that need to be applied to overcome a constraint while performing Service Confirmation on Amended SRM Purchase Orders?

The create confirmation button gets greyed out when the SRM PO is amended, however if you try and do service confirmation using ML81N for the same PO from the backend, it works.

The scenario is extended classic.

Cheers

Tridip