iCal-GMAIL calendar integration. Aweful forced handling of gmail calender email-alerts via Mail

iCal attempts to hand/send the gmail calendar email alterts via MAIL. how to stop that - gmail handles that itself - while still allowing pop up notifications?

I dont use the program Mail, nor will I ever.. And it keeps on opening up whenever and email alert is supposed to be delivivered regarding my gmail calender account - but gmail handles that itself automatically. this is really bothering.