Creating the Purchase requisition for SR form

Hi Team,

I found out on the below link that we can create the PR from SR form via parts requirement process, we are already using this process for the IR/ISO cycle however now we need this for the PR also actually when we try to enter an item of billing type 'material' for which the source is defined as 'supplier' in item master, we are not able to proceed as system is always taking the IR/ISO route whereby the parts are sourced from an inventory organisation.Our requirement is to generate a purchase requisition for buying the part form FS and using