This question is probably better directed to an MS Access developer's forum.
It appears you need the VBA code to put into the click event on the Access form button. Since I am not aware Access offers a viewer component which I believe such a circumstance would require the presence of a copy of CR to run the report and while you may call up the report it would run in CR not Access. Perhaps there will be an MS Office developer who sees this post and offer up the VBA code and correct any misinformation I may have offered.
If you have all that sorted out you can pass parameters to the CR report object. The parameters exist in a collection and I believe you can reference them by name or index number. I dont have the reference in front of me, but I have done this in .Net. If you look on the web you should be able to find the syntax needed for VB and then port it the appropriate Access/VBA code.
Here is a .Net example
Here is another
Perhaps they will get you pointed towards what you need.
Regards
John W.
Edited by jkwrpc - 18 Feb 2010 at 11:57am