...now, I got it!
the trick is - don't to follow the given notes - just follow the button "Addon&Upgrade". This will lead you to the upgrade pack of ST-A/PI 700 SolMan. This can be installed via SAINT!
The pack I got from Solution Manager MOPZ, is only valid when you have 700 SolMan already installed.
So, the how to is: do not use MOPZ; download the installation / upgrade pack for "01N_700SOL" and load it into SAINT; be sure that no filter is set in SAINT (this was another mistake); choose the pack and install.
fine, thanks to DIego.