Here is the list of Debug Commands for Cellular cards.http://www.cisco.com/en/US/docs/routers/access/1800/1861/software/feature/guide/3hwicdm2.html#wp1256850
This should work. Since we are using two HWIC cards (two wan interfaces), its is equivalent to two point to point links to the same destination. So this can either be used for backup/ redundancy or increasing the total throughput.
If you want to change the ports and run different instances of syslog monitor than you try this command switch(config)#logging host X.X.X.X transport udp port ## . This will change the port that the syslog messages are sent on and you will just have ...