Joining Cube data with a single column from OLTP table

Hi ,

I have a requirement wherein we have data in DW Cube regarding all orders , their items , catalogs etc . but the authorisers of the orders who are employees of the organisation itself ultimately mas to userid which is a column in a OLTP table .

In order to retreive complete details of the orders we need the details of the authorisers for which we need  to refer the User table via userid . And we might  need to design our SSRS reports around this entire data .

Any help on how i can do easy and quick mapping between the cube and the OLTP table ?

Thanks