TextObject VB.NET cant it be done??

Hi,
I cant find out how to add a report parameter or formula via vb to a TextObject.

In the crystal designer, you can drag and drop a formula or report parameter into a textobject, it will look something like this

Report from [ {?FRMDATE } ] to [ {?TODATE} ]

FRMDATE and TODATE being report parameters passed in, but I cant seem to do this via VB.net, Evan if I load an existing report with the parameters in it, as soon as I set the text property the parameters turn into plan text

so with the above done in the designer I would get on the report

Report from [ 01/01/2010 ] to [ 31/01/2010 ]

but If I try to do this in vb.net like this sort of method

mytextobject.text = "Report from [ {?FRMDATE } ] to [ {?TODATE} ]"

I get the raw text on the report like this, note the parameters are raw text not the values

Report from [ {?FRMDATE } ] to [ {?TODATE} ]

anyone know how to insert a parameter or formula into a textobject via vb.net ?
or is it even possible with crystal.decisions.engine ?

Thanks,
Ryan