Asterisk as IVR from Mitel 3300

Hello to everybody

I need help to connect Mitel 3300 with Asterisk. I found many documents but i can’t resolve yet. I have a SIP license of Mitel and y tried to maked a connection , but I received an authentication error 400 and in another time error 500.

Somebody talked about a document o Mitel 06-5160-00002.

Anybody can sendme a detailed explanation about this subject?.
I really have an Elastix version 2.5.

Thanks

Neither 400 nor 500 are authentication errors. 400 is “your request is malformed”, and 500 is “sorry, I am broken”.

Please provide the exact and complete request you sent and the exact and complete response you received, e.g. using sip set debug on.