Refnums in FTI

Hi All,
In OTM 6.3, FTI allows KPIs to be written using refnums. The data structure has been modified to allow refnums to be populated in the FTI DB.
Has anyone tried this with earlier versions of 6.x? Does the entire ETL piece need to be re-written or is there a workaround to bring in refnums?
Regards,
Ashwin

Also can a higher version of FTI be installed on top of a lower version of OTM? I.e. install FTI 6.3 on top of OTM 6.2?