Hi,
It should not be a problem. I performed the same operation on a CVI 7.1 with Win XP Pro. and was able to get the desired result.
You can check for the set control type with:
GetCtrlAttribute (panel, ctrl_id, ATTR_CTRL_MODE, &value);
after you create the numeric control. Default is value == 1 (which is for type: HOT)
Dwivedi