NLS SQL syntax

Hello Informixers, who can tell me why Informix executes the next two statements in a different way: SELECT something FROM somewhere WHERE proc() MATCHES "*text*" SELECT something FROM somewhere WHERE "*text*" MATCHES proc(). when proc() returns single NCHAR string containing national characters. It seems to me that second statement works correctly while first returns wrong (but stable) sequence of rows. Both statemets work correctly when proc() replaced by name of NCHAR column. I use Informix-Online 7.12 on Sparc Solaris 2.4. Any help would be appreciated Leonid