asterisk users - Apr 2005 - choose audio codec with chan_sccp driver and 7920 wireless?

Hiya everybody - I got myself a cisco wireless 7920, and have had no 
trouble at all setting it up.  I used the easter2005-testing version of 
the chan_sccp driver from chan-sccp.sf.net. Calls in my LAN are crystal 
clear and sparkling.  I set up my firewall to allow connections from the 
exterior, and have now made and received calls over the device from my 
work wireless.  Too cool.  It's a little choppy from work 'cause of 
upstream bandwidth limitations (512/128) on both ends, so I bought a 
g729a license from Digium and registered it.  Everything seems OK there; 
asterisk sees it and loads the module and registers it properly on 
startup, including the translation between g729 and signed linear.

So I popped open sccp.conf and went looking for the disallow= and allow= 
lines to modify to my g729-liking heart's content, and .... there was no 
mention of them.  I tried placing

disallow=all
allow=g729
allow=ulaw
allow=alaw

first in [general], then in [SEP<myMAC>], then in [mywirelessline], but 
the sccp driver doesn't seem to allow codec control via this method.  I 
couldn't find in chan_sccp.c where it checks sccp.conf for anything 
related to codecs.

Does somebody have any experience with this procedure?  How can I tell * 
to use the g729 codec for this device or line?

Can/Should I try something like the following in my dialplan?

SetVar(SCCP_CODEC=g729)
SetVar(CODEC=g729)

Thank you for any suggestions!

Mojo