db1 = ibec_CreateConnection(....);
db2 = ibec_CreateConnection(....);

set trparams 'isc_tpb_read_committed, isc_tpb_rec_version, isc_tpb_nowait';

execute ibeblock
as
begin
  db1 = ibec_CreateConnection(....);
  db2 = ibec_CreateConnection(....);

ibec_UseConnection(db2);
SET TRANSACTION
  READ WRITE
  ISOLATION LEVEL READ COMMITTED RECORD_VERSION
  NO WAIT;

ibec_UseConnection(db2);
EXECUTE STATEMENT 'SET TRANSACTION ' +
  'READ WRITE ' +
  'ISOLATION LEVEL READ COMMITTED RECORD_VERSION ' +
  'NO WAIT';