Force parameter to be optional

I have a CR that is based on Sql Server 2008 stored procedure. The procedure accepts optional arguements.

Now, i want the CR to ignore all parameters that are not selected but it keeps asking and asking. The parameters are auto--created by CR when creating the report from the SP.

Tried to set the optional property of the parameters in my report but it is grayed out/disabled?

Any work around that? What would be the possible network overload if i send parameters empty when they ll be used for nothing at all?

Much like executing a cmd query with parameters dont bother about missing/omitted parameters, i want my cr to ignore parameters if i dont specify them at all.

hope it is clear. my english is bad.