Benjamin,Try this ....show user. Also, debug your ppp sesion with the following and see if you can see the username..usedebug ppp negotiationand debug ppp authenticationalso you could debug your aaa withdebug aaa authenticationand debug aaa authoriza...
Yes this can be done locally or in cisco secure.I have done this with Cisco secure 2.5 with TACACS+, but not with the freeware..Why don't you download an eval version of Cisco secure and try it...The liscence is good for 30 days....I believe.
Stephane,If you are using a dialer interface put the authentication method under it..i.einterface dialer 1encapsulation pppppp authentication chaphope this helps