replicating tsearch2 across versions of postgres

I am getting the following error(s) when replicating tsearch2 from v
7.4.x to v 8.1.0

remoteWorkerThread_1: copy from stdin on local node -
PGRES_FATAL_ERROR ERROR: function "spell_init(text)" does not
exist(at)4000000043a9708d21558414 CONTEXT: COPY pg_ts_dict, line 1,
column dict_init: "spell_init(text)"

the problem is that the function signatures have changed

spell_init(text) is now spell_init(internal) so the function can't be
found on the destination node.

My solution is to not replicate the internal tsearch2 tables. Is this
going to be problematic ?

Is it possible to add the old signatures back for backward
compatibility ? Something like a tsearch2-compat lib ?

Dave