Hmm yeah, HPUX 11.11 is a problem :(.
I would suggest this.
1) Upgrade PA-RISC to DP 6.2. It's a straightforward upgrade - just omnisetup.sh.
2) Follow the DP 6.2 Installation & Licensing Guide on how to migrate from PA-RISC to IA-64.
3) Once everything is working in the IA-64 upgrade it to DP 7.0 (another simple omnisetup.sh).
I have extracted the relevant pages for you.