Passing variable values from WAD to BEx

Hi Experts,

I am working with a query which is included in a web template. At the top of this template, I have several variables included in drop down boxes for the user to navigate through the data.

With clicking at "open in Excel" a BEx-Query is started.

My question: How can I pass the variable values from those drop down boxes to my Query in BEx?

The current HTML code for starting the Excel BEx-Query looks like this:

http://sapserver:port/x/x/x/rsr_bex_launch/bexanalyzerportalwrapper.htm?QUERY=Queryname

Thanks in advance

Marco