Secondry Resource confirmation

Dear All.

We are using Process Order, for some phases we have assigned secondry resources. If my yield quantity is 100 Kg then i require 10 Hr in phase & also in secondry resources while confirmation of phase if i do partial confirmation for 50 Kg system automatically calculate activity of 5 Hr like same if i confirm secodry resource there is no option of yield quantity so that it always consider as 10 Hr so please suggest is it possibel to active yield field in confirmation of secondry resources for calculating activity???

Regards..