asterisk users - Jul 2010 - connecting to EON millenium getting 405 message

I am trying to connect asterisk to EON millenium with SIP.

I am getting a 405 message back from EON

Looks like asterisk sends a register command , EON says OK
then asterisk sends sip options and EON says 405.

Is there a way not to send sip options?

THanks,

Jerry