[Users] AVP and Radius question

[Klaus Darilion]

Hi!

I'm quite new to avps - in fact I have not used them yet. Thus, please 
apologize if my questions are dumb.

In my setup, (open)ser receives in the radius response two attributes:
  - RPID
  - prefix (for a call by call provider)

In ser I have to add the RPID header using the RPID attribute, and 
prefix the number in the request URI with the prefix attribute.

As far as I understand the auth_radius module in 0.9.4 supports 
receiving various radius attributes and storing them as AVPs.

First, in ser.cfg I will add the RPID header. Is the function still 
append_rpid_hf() or do I have to use another function for generating the 
RPID header out of AVPs?

Afterwards I have to prefix the request URI. Can this be done with 
avpops functions? I only found avp_pushto, which will replace the 
request URI - right?

Can I store any arbitrary Radius attribute in AVPs or only predefined ones?

regards,
klaus