BAPI_ALM_ORDER_MAINTAIN

Dear All,

I have requirement to change quantity, basic start date & Work centre (In an operation) of a Process Order. I am trying to use BAPI_ALM_ORDER_MAINTAIN. I am able to change the work centre, but in case of quantity & Basic start date system is throwing error that, this Order type no supported. It seems, since the BAPI is more For Maint./Service Orders so it is not supporting Process orders.

Just wanted to confirm, is this the standard behaviour os some links has been missed.

regards