As I said earlier I think it's going to be a bug within LMCE and it's db. Please run the following command from a command line on the LMCE machine:
sip set debug ip 192.168.0.3 (put in your IP address of you LMCE machine that the SPA is trying to communicate on)
The post here so I can see what it is doing. Since there is no peer found running sip show peer won't show what's going on between the SPA and LMCE, using the "IP" will.
Asterisk is not finding the peer name you are trying to register with the SPA. There is either a user name or password not matching up with what Asterisk is looking for based on what Asterisk is pulling from it's db, normally Asterisk pulls this info from it's AstDB.
Also while your at it, copy and paste your "sip.conf" file here, you can find it on the LMCE server /etc/asterisk/sip.conf, oh wait a minute, there is no sip.conf on the LMCE machine I have under etc/asterisk..... Either it is located somewhere else and I'm not aware of or found yet, or, it's been renamed to something else, or, maybe someone forgot to include it in the build....
I will be tied up till after ten tonight so I won't be able to get right back to you, but I will look at it tonight. Stop pulling your hair out, I'm sure there is a simple answer to it all.