nonlinear dynamic analysis using SAP2000?

[geo1234]

I could really use your help on a matter conserning SAP2000.What i'm trying to do is study a steel frame and its plastic mechanism.I'm having real problems with the nonlinear dynamic analysis.How can we assign the plastic1 element in SAP2000? Should we add joints close to the given ones and draw the Plastic1 Element there or should we draw the whole frame by Nllink elements?Also at which directions should we apply the nonlinear behaviour?
Its easy to apply a pushover analysis in SAP2000 and see where the plastic hinges are but how about the nonlinear dynamic analysis?
I would be really glad if anyone could reply to my question since i can't find any help at all about this matter(plastic analysis with SAP200nl) or give me some advise where i can find something useful on the Internet
Thank you
George