How to open a javascript:__doPostBack link

I’ve successfully automated a pop-up form but having trouble submitting the form using the click or xclick command for a button on the form that has a link address of “javascript:__doPostBack” command. Anyone run into this previously and know the fix? If so, if you can provide some sample code to get me started it would be appreciated!

Can you use xclick | imageOfButton.png ?

I’ve never tried this before. Do you have or know of any sample script that I could try and mimic/customize to work for my situation?