This is actually 2k pro, not 2k3 server forum - see forum931.
Why do the folders need to be 'continuously synchronised'? Doesn't make sense - if they are both being heavily accessed over the network, then continuously synchronising them is going to seriously interfere/possibly corrupt that access. if they're not heavily used, why don't you just have one folder, with regular backups?
You can schedule a job that just copies one to the other (eg, batch file using xcopy?) and runs every x seconds.