When ppp is started, if ipv6 comes up correctly, any files in the /etc/ppp/ipv6-up.d/ directory will be run. Create a file and call it, say, /etc/ppp/ipv6-up.d/start-ppp0-ipv6. This file holds the ipv6 range given to you by aaisp. You'll also need to tell it that the default route is through the new ppp link as this doesn't seem to happen automatically when ppp is started. Include the following lines in the file:
/sbin/ip -6 addr add 2001:8b0:xxxx::1/64 dev $1<br />▼
route add default dev $1 </tt>
addr add 2001:8b0:xxxx::1/64 dev $1 <br />
Replacing xxxx by the appropriate address given to you by Andrews & Arnold. You'll need to <tt>chmod 755</tt> the file you just created so that it can be executed when ppp comes up.