Solved :P
I must be blind to not see it before. But maybe my blindeness may be helpful to someone with similar case:
The directive 'iroute' (the one stored in common name file of client in) was not loaded by OpenVPN daemon.
That's why routing was working until virtual adapter of remote box. OpenVPN simply did not know how to route to physical Adapter on remote LAN.
The reason was that first letter of the common name (taken from cert) was uppercase - and the filename displayed was whole lower case.