Hey Jack ..
For Feeder type SAPSRM_FEEDER_BUPA_SUP you got to know the feeder class which is /SAPSRM/CL_CLL_POWLT_BUPA_SUP ( t code POWL_TYPE).
In this class there is a method called IF_POWL_FEEDER~GET_SEL_CRITERIA. We can modify the attribute mt_selcriteria in order to change the value help used...
You may have to debug to be able to figure out ..
Regards
Vinita