as i read the manpage to Tversion, the client first sends something
like 9P2000[.extension] and the server responds with something like
9Pnnnn. so if we add the extension to like kfs or cwfs, we can
respond with 9P2010 or something and the mnt driver will use the
Tmove rpc.

but looking at the implementations... we are in trouble... 

cwfs:
	/*
	 * Should check the '.' stuff here.
	 */
	if(strcmp(f->version, VERSION9P) == 0){
		r->version = VERSION9P;
		chan->protocol = serve9p2;
		chan->msize = r->msize;
	} else
		r->version = "unknown";

lib9p:
	respond(...):
		switch(r->ifcall.type){
		default:
			assert(0);

so, just using "P92000" and send blind Tmoves to lib9p based
server will crash them...

using anything other than "9P2000" will most likely result in
the Tversion to fail with old servers.

so uriel has a point here...  negotiation my ass...  but this attach
name hack sucks big time... 

--
cinap