Date functions on Olap data in RS

[cip]

Hi  all!
User is choosing date on the prompt page of the ReportStudio report.
Report should be filtered on that day and a few relative days (last day of the
previous month, last of the previous year, etc.).
How to get these few dates from the parameter. If it doesn't work using functions,
is there any other sugestion for this kind of requirement.

Data source is a PowerCube.

Regards
Cip