'm using this macro:

#showtooltip [combat] Shadowmeld; Stealth
/cast [combat, nostealth] Shadowmeld; [stance: 0] !Stealth
/cancelaura [modifier:Shift] Stealth

and it works except for the /cancelaura part. I can get that to work if I just make it:
/cancelaura [modifier] Stealth

and I hold ALT while pressing it, but I want to use shift. Only way I've been able to cancel stealth is to bind another button to Shift+V (V being the macro button keybind). Otherwise you can't cancel stealth when using the macro.