CR Parameter field Question

Ok, so here's the thing:

I have a VB(6.0) project and a CR report in it. The report draws it's data from a stored procedure. Now, one of the fileds appearing on the report is called Code1, and in this particular case it has values 010, 100, 110 and 230. These numbers represent the item codes my company uses for something not important to us right now ... On the report, Code1 is located in the details section.

What I can't seem 2 figure out is this:

I made a parameter field called Selection. The value type I want to work with is a String. Code1 field also has the same value type. On the " Set default values" tab I entered earlier mentioned values ( 010, 100, 110, 230 ) and assigned description to them.

Now, when I use my parameter field " Selection " with the Select Expert, the formula looks like this: {spProSastavnicePrintQuery.Code1} = {?@.Selection}

The thing that troubles me is when I call upon my report, the entire Details section is EMPTY. BUT! When I use Select Expert and manualy enter

{spProSastavnicePrintQuery.Code1} = 100 for example, the report comes up the

way it's supposed to .. in the Details Section it generates only the data with the
Code1 containing the value of 100. What is the problem ?

Hope this post isn't too confusing .. Thnx in advance ..is it like this
{spProSastavnicePrintQuery.Code1} = {?@.Selection}

or

{spProSastavnicePrintQuery.Code1} = {?Selection}

?Parameter represent parameter and @.Parameter represent formula