Hi,
I have a network with some base station linked in wds mode, and ospf for dinamic routing.
This base station are all with two radio cards where one of this is part of my backbone and the second one is set like hotspot.
To authenticate my users I have a centralized RADIUS SERVER (freeradius) that is actually working ok if they login from mikrotik hospot login page!

I have some clients that actually have a cpe mikrotik based and are connected to my hotspot interfaces.
When they want to surf my BS provide to them a login page (the hotspot login page) but all times they have to write username and password to login in.

I would like to write their user name and their password directly (to authenticate them on my network) on the cpe to permit to them to surf on the net without write any user and password.

In some words I want to authenticate cpe of my clients to my hot spot using "RUNTIME HTTP-CHAP or HTTP-PAP AUTHENTICATION" not from browser but directly from cpe.... Like a DSL modem.

Do u think is Possible?

You can set up pppoe server ,and autenticate via radius !

do u think that hotspot and pppoe can be activated together?

yea ,a do it many times ,and works perfectly .No another configuration is needed for passtrough hotspot !

Yes, I have hotspot and pppoe running together, working fine. pppoe seems to be the answer to your question.
Jay