I have mikrotik with 3 packages (differents speed and bandwidth). For each speed I have defined IP pool and assign IP's for:

Package 1 = xx.xx.xx.10-xx.xx.xx.30
Package 2 = xx.xx.xx.31-xx.xx.xx.90
Package 3 = xx.xx.xx.91-xx.xx.xx.200

I have limited speed in simple queues.

Speeds are limited for outside traffic. Inside traffic is unlimited.

Because I have to limit bandwidth, I'm using free radius.

How to count only outside traffic?

Any comments?

Is it possible or not?

you can account outside traffic only by using NetFlow. radius statistics is only for user's interface, all user's traffic

Any hints about this? How to implement this?

your billing system should support NetFlow receiving

So, I'm using free radius. Does free radius support netFlow?

Any other client which support netflow?

UTM5 supports it, as far as I know