Hi DC,
Welcome to the board I confess I know next to nothing about Mac, but until someone helps you out, you can work around this problem. Add an image control to your form. Set the special effect to raised. Set the button click event to perform the action you wish. To simulate the button animation use the mouse up & down events. See example code below.
[VBA]Private Sub Image1_Click()
VBA.Beep
End Sub

Private Sub Image1_MouseDown(ByVal Button As Integer, ByVal Shift As Integer, ByVal X As Single, ByVal Y As Single)
Me.Image1.SpecialEffect = fmSpecialEffectSunken
End Sub

Private Sub Image1_MouseUp(ByVal Button As Integer, ByVal Shift As Integer, ByVal X As Single, ByVal Y As Single)
Me.Image1.SpecialEffect = fmSpecialEffectRaised
End Sub
[/VBA]