Transformation - Rule group problem

Hi Gurus,

We are currently NW2004s SP 8. I created a datasource in BW. Created a transformation between infocube and the datasource. Except one info object 'a', all other fields appear's in the Rule group(standard group) .Info object 'a' is available in datasource as well as info cube.

Question :- Does anybody came across same situation ? Is there a way to add a info object into the rule group ?

I really appreciate your help/suggestions on this.

Rgds,

SeVu