Query inside RTF

Hi, in my database I store RTF files inside a Bytea field. Now a
customer is requesting a search inside RTF fields and I'm trying to
implement it by issuing this query:

select
  *
from my_table
where
  cast(rtf_field as varchar) like '%condition%'

This works ok when the condition doesn't include accented chars. RTF
escapes accented characters as "\'f1" for í, "\'f3" for ó, and so on.

To escape \ and ', I'd read it shuld be used \\ and '', so I thaugth
that a like '%diagn\\\\''f3stica%' should get "diagnóstica", but it
doesn't.

Any hint on this?

--
Leonardo M. Ramé
Griensu S.A. - Medical IT Córdoba
Tel.: 0351-4247979