BI - Cube Concept and MDX Query Help

In a [Mondrian](http://community.pentaho.com/projects/mondrian/) Schema, I have a fact table for Sales, a dimension table Time and a dimension table Client. I need to create a [Saiku](http://www.meteorite.bi/products/saiku) report where i can show how many clients joined per year. I have a the Time dimension and a join_date in Client (which DO NOT link to the Time Dimension key, is just a date field),. If I create a cube adding Join_date as a Level of the Client Table, I wouldn't know how to filter that latter in the Saiku. Does anyone know how is the best way to add JOIN_DATE on client? I just need a report: Clients that have joined to the company by year. And how should ` work in cubes? When i tested using this `, it was not visible in Saiku...