GroupWise automatically inserts the user signature after the message text but before the reply/forward marker, if any:
Notice that the marker ends in a space character.
You can modify your applet to prefix the disclaimer with this marker. This should induce GroupWise to behave as desired.
For an HTML-format disclaimer, you can hide the marker from normal view by enclosing it in a tag whose font color is white, or the font size is very small.
Note: The behaviour described above applies to GroupWise 6.5x and below. You may need to test this strategy with GroupWise 7.x.
I hope this helps you.