Forms :: Passing Value To Combobox On Load? (Access 2010)

I have a form design where to enter a new "system" (what we call a new group of members) you have to specify the representative (the member that will represent the system).

If the system is new AND the representative is new, then both need to be entered. Typically this will be done through the "New System" form that has a combo box for you to choose the representative (but the representative won't be there!). If the representative is new as well, then the user clicks "Add New Rep" which is located next to the combo box.

This is where things get tricky, I'd like to use only 1 form to load a new rep. My idea was to use an openarg on the docmd.openform method that specifies what the control should be.

Code:
DoCmd.OpenForm "RepresentativeAddNew_Form", , , , , , "System_ID|" & Me.System_ID

That is the code that is called when the user click "Add new rep" and in the on load event I have this code:

Code:
'Use this version if the ID is text
Dim x As Variant
Dim strControl As String
Dim strID As Long
'If parameters exist, use them

[Code] ....

My goal was to pass the value to the combobox and turn it off, that way they can't change anything about it. This was nice because if the openargs is null (there were none passed) then the combo box would be enabled and the user could select the school that way.

But this doesn't work, for some reason, the combo box has NOTHING done to it (I have the control name correct).

Is this due to the way comboboxes work? Or am I missing something?

I should point out that the on-load event was not my idea, I found that online but makes perfect sense. I was trying something similar but was trying to use global variables because I wasn't aware that OpenArgs was a valid control!