Yes, I think I found the issue, the SIP ALG on the ASA was holding connections open, disabled the SIP and it appears to be working now.

1. Brekeke Product Name and version: SIP Server ver 2.4.5.5 2. Java version: Sun java 6.2 3. OS type and the version: Ubuntu 10.04 4. UA (phone), gateway or other hardware/software involved: Cisco ASA 5. Select your network pattern from http://www.brekeke-sip.com/bbs/network/networkpatterns.html ...