hi,
I have not tried but, if I was in your situation i' do:
- Elect a machine at nim server and install a fresh 5.1
- make a standard nim master installation
- try it installing a 5.1 client
- Create new LPP and SPOT naming LPP433 and SPT433
- try to install a 4.3 client.
(I have done it with 433 and 432)
bye