MAF sensor help

[markp90]

hi guys

after reading through a few threads decided to give the maf sensor a clean.
went and bought the sensor cleaner and a t20 torx bit and went to open it up however the bit doesn't fit?

I'm not very good with what different bits are called but can someone please tell me what i need to use to take these out to open the sensor? Its like a T20 fitting but has a small piece of metal protruding from the centre of the bolt?

hope this makes sense...

thanks
Mark