Converting timestamps from other timezones

I need a method of converting timestamps from remote transcription services to my local time when documents are received.  In Cloverleaf, possible options are xlate DATECOPYOPT & a Java UPOC fragment called ‘tnToDate’ that I might be able to embed in an xlate.  The idea would be for the remote vendor to give me their time plus their offset from GMT.  I would compare that to my own offset & derive an accurate local time, regardless of daylight/standard time.

Has anyone done this?  Is there a better approach?

Thanks!

Ted Mech