I'm sorry for long silence - just digged out techs.
First, my reply to jaclaz:
I can't use L2TP, PPTP etc. 'cos, as I said, server use IKEv2 connection, that's what it did and that's what I definitely can't do anything
And yes, I can ask "someone" to send me PSK and that "someone" will send me this one, but it will not make me happy 'cos My PC won't messing around IKEv2 with PSK auth and it's a key of my question
Well, generally answer for my question is:
It's impossible to use PSK for IKEv2 authentication in Windows 7 machines because Windows 7 don't supports such auth for this type of VPN.
Hope my little research will be helpful for somebody else.
And thanks for everyone for their advise.