How can I enable the "convinience" menu on a maxidot via vag-com?

Close the car door, put seat belt on and ignition

How can I enable the "convinience" menu on a maxidot via vag-com?

And if you have MY05 or MY06 car, you cannot. It's a feature in MY07 cars onwards.

Of course, if you update your maxidot, CAN gateway and convenience module to MY07 or MY08, then you might have the option in MaxiDot.

From where and how can I get these updates?

From where and how can I get these updates?

From your dealer maybe. But be prepared. You have to physically buy new modules and that's expensive. There's no software update possible or even available.