Passing parameter from main report to subreport

Hi All, please help me...

I'm using CR XI. i have created two subreports which are placed in the detail section of main report.

Both of subreports take data from Mysql stored procedure which use 1 parameter, that is 'CustCode'.

Now, how to pass the value of 'custcode' field in detail section of main report to the subreport parameter ?

until this time, my effort still fail

I use Mysql 5.0 w/ mysql connector v5.1

Thanks b4