Continuous Command Button Event

Hi
I've got a text box with two command buttons (cmdincrease and cmddecrease) next to it. The text box hold the time in the format hh:mm:ss

I've written some code that allows me to increment the time from right to left ie if time is 09:11:23 and I press the cmdincrease command button the time gets incremented to 09:11:24 the code works fine and I have placed it in the mousedown event of the button, but my problem is I need to click the button
each time to execute my code, does anybody know how I can do it such that if I keep the increase command button pressed (using the mouse) the mousedown event is executed until I release it.

Maybe there's another event into which I need to place my code.

I am trying to mimic the setting of the wait times like they do for the screen saver in the settings section.

Many thanks in advance

Raj