Hi Iñaki Larrañaga,
We have done the upgrade successfully with the bove mentioned strategy. It worked lyk charm without any issues.
a) Unicode Pre Conversion Phase
b) UCCHECK, SPUMG, Data conversion
c) Adapting custom programs to unicode
d) Export of Development Server
e) Uninstall SAP and Database Server
f) Upgrade OS to Hp-Ux 11.31
f)Install Development server R3 4.7 ext 2.00 with unicode version and Oracle 11.2.0.2 and import unicode database.
g) Unicode Conversion Post Conversion and Completion Phase (SUMG)
i) Upgrade Development system from SAP R3 4.7 to SAP ECC 6.0 EHP5
In one down time OS ,Oracle will be latest and SAP will be unicode system.Then you do SAP upgrade,
Thanks,
Pankaj