Asterisk realtime - extensions ansd sipregs

Hi, Using 1.6.2.8. I have got asterisk realtime working with regard to sip users and extensions
to a certain extent. I have TWO issues however,

  1. The context in realtime extensions ie

[context]
switch=>realtime

is still static and requires a reload , this defeats the whole purpose of the realtime extensions as i will need
multiple contexts.

2.I want to define the register=> variable as realtime, i believe sipregs is the way to do it but what is the format of the table?? Is sipregs the way to do this firstly or do it have to be done in the sip.conf file.

Also i suppose to unregister asterisk as a UAC one should just remove the register=> statement, but again i want to do this in realtime without a full reload as i could have thousands of users.

Thanks

Apologies there is a THIRD issue as well

  1. To receive incoming calls when SIP peers are defined as realtime one needs to put an ip address in the host field as opposed to a domain, i can’t use it like this. Is there some way round this or something i’m doing wrong.

Thanks