The tun.ko is ok, it loads nicely. Many many many thanks !!!
In the "OpenVpn Settings" app, my connection ask me for a password, I see "auth", then nothing, I fall back in front of the "select to turn on OpenVPN tunnel" button.
I have tried with stock libcrypto.so and libssl.so, and then with those from openvpn-binary.zip at hxxp://sourceforge.net/projects/tunneldroid/files/
The OpenVPN app still don't want to establish the connection... In no ways... And no log message in dmesg at all (neither for tun)
So it's enough for this night, but if someone have an idea, you are (really) welcome !!!