Changing Property Settings By Code

This is getting into some stratospheric territory for me.

I am trying to change the visibility property of a label and corresponding text box, based on the contents of a different combo box. cboHow is a combo box that uses a value list as its row source, since the content of the list won't change. There are three fields that I need when the content of cboHow = "FIS". Otherwise I don't need them and I don't want to see them. My code is below:

Private Sub txtFISDepartmentNumber_BeforeUpdate(Cancel As Integer)
If cboHow <> "FIS" Then
lblFISDepartmentNumber.Visible = False
txtFISDepartmentNumber.Visible = False
Else: lblFISDepartmentNumber.Visible = True
txtFISDepartmentNumber.Visible = True
End Sub

At the moment there is no error code, but the label and text field don't respond by becoming visible/invisible when the contents of cboHow changes. Do I put this code with the txtFISDepartmentNumber or in cboHow? and do I use BeforeUpdate or AfterUpdate? Should I have a separate If..Then..Else for the label and the text box?

I have been playing around with this for several hours now and seem to be going in circles.

I am using A2K