Does RouterOS support IPSec authentication using XAuth (username + password) RSA (certificates)? I've noticed that it supports Hybrid RSA but this is different than what I need.

Unfortunately, changing IPSec server's configuration is not an option. Just to exclude: other VPN clients supporting this authentication method and configured similarly work flawlessly but using my RB450G as a IPSec client fails to connect. 

If XAuth RSA is not supported, can it be added in a future version of RouterOS ipsec?