I have the AC XY/MS kit, i'd like to know how to convert it from MS to XY?

To convert the suspension from M/S to X/Y. You should should be able to unscrew the main thumb wheel on top (and under) of the plate so that the metal pin comes free and can rotate to one of the other 4 slots. You shouldn’t need to completely remove it. 

 

Attached is a diagram showing the degrees for the XY set ups. You can download this if needed.

 

Stereo Windshield Kits from Rycote on Vimeo.