Comboboxes with stored procedures

[Sergio Florez]

In an access project I can define the source for a form
to be a stored procedure and i send the parameters
through the inputparameters property.

A combobox does not have inputparameters, so how can I
use a Stored procedure that needs parameters as the
rowsource for a combobox?

I tried programatically like this:
Combo1.RowSource = "exec
spProductosCotizadorxCategoria " & [IvaCpU] & ",7," & [PC]
Combo1.Requery

It didn't work.