Mix of releases SE 4.0 and SE 5.0, and I4GL 4.0 and RDS 4.10

I've got production management software (made in ESQL-C, I don't have source code ) which only runs with SE 4.00 databases (according to the vendors). I've got accounting/sales management software (in Informix RDS 4.10, I have source code) which runs with SE 5.0 databases. Both versions are installed in our Unix system, and environement variables are set for users according to the programs (and therefore version) they use. Now I have to alter a RDS 4.10 program so that when it updates an SE 5.0 database (i.e. when something is sold) , stocks in a table in a SE 4.00 database are updated accordingly. The only way I can think of achieving this is unloading sales data (SE 5.0) to a plain text file, then, whitin the RDS-4.10 program, RUNning WITHOUT WAITING a shell script which changes environement variables to the values needed for SE 4.00, and calls a 4GL program which loads the text file and updates the SE 4.00 database. Anybody think anything could go wrong? and Any better ideas? Thks