I know this is not a direct answer to your question, but I would try to convince the customer to upgrade to V7. It may not be cheap because there are some hardware upgrades, including the processor card, but V7, especially V7R2, has a whole slew of really cool backup and system recovery options to many different kinds of media, and there is also a brand new web-based course that is top notch and shows you how to use all those methods, in addition to some background on how all the system components interact together.
All you can really do otherwise is keep many backups you know are good, and especially keep one offsite and rotate it out once in a while. I am not quite sure with V3 being well past end of life whether they would repair it or try to make them upgrade it.
Don Bruechert, Voice Comm Analyst II
CareTech Solutions @ Holy Family Memorial
Manitowoc, WI, USA