Access Runtime Application Problem

Here's the situation:
I have a database application that runs in Access 2003 runtime mode. I
have a form that runs in Datasheet view. What I want to be able to do
is allow the user to change the sort order while viewing this
datasheet form. I have included the normal Access sort ascending/sort
descending buttons on a custom toolbar. On my PC, with full version
Access installed, these sorting buttons are enabled and I can sort,
even while running in runtime mode.

Here's the problem:
My users who run without full version of Access installed can see the
buttons, but they are greyed-out/disabled.

Does anyone know of a way to enable those buttons?