OK, can you point me to the change that makes the two chains incompatible? I can't find it...
"New Peering Marker
On Sept 1rst 2011 at 00:12:51 UTC (in under a week), the new client will switch over to a new Ixcoin-specific pchMessageStart peering marker from the original Bitcoin marker. This change was recommended by a few although we haven't had reports of any issues with this yet. Better safe than sorry. The updated Ixcoin nodes will not be able to communicate with non-updated Ixcoin clients after that date. This will require a restart of the Ixcoin client on or after Sept 1rst. (commit)"