Hi:
As a rule of thumb, I hardly ever specify my Enterprise Guide parameters to be enclosed in quotes, as I prefer to modify my program code accordingly -- use quotes where they're needed or don't use quotes where they're not needed. It seems to me that your best bet for help with this is to contact Tech Support. You have two issues -- how parameters work inside the world of EG and then how input parameters work in stored processes. The fact is that you may have to slightly modify your code when you create a stored process from your EG parameterized task.
Partly, Tech Support will have to look at the selection code in your stored process and help you figure out the best way to specify the parameter. Even if you specify the Date type for your input parameter (in the stored process) in order to get the little calendar box to come up (for the stored process prompting), the value that's being sent will still be a text string. (01OCT2007 versus 17440 -- which is the "internal" number for today as a SAS numeric date value);
This may be slightly different than how you were dealing with things in the parameter manager in EG. But, the bottom line is that you probably want to uncheck the box for automatic quoting and deal with the need for any quotes in your code or your generated code (by inserting code into your task). Tech Support can help you with that task by identifying the correct type of the variable in your comparison and they can help you set up the input parameters for the stored process the correct way.
cynthia