If your Steam account has always been a Steam account, then yes; instructions below. If it's been converted from non-Steam to Steam (as mine has) then I'm pretty sure you have to use Steam.
Instructions for account that's always been a Steam Account:
Open the standalone SK client.
Press the Facebook button.
This will open the SK site in your browser. Press the Steam button.
This will redirect to the Steam login. Login normally.
If all went well, you should now be logged into the standalone SK client on your Steam account.
Once again, this doesn't seem to work with my account that's been converted from non-Steam to Steam.
If your Steam account has always been a Steam account, then yes; instructions below. If it's been converted from non-Steam to Steam (as mine has) then I'm pretty sure you have to use Steam.
Instructions for account that's always been a Steam Account:
Once again, this doesn't seem to work with my account that's been converted from non-Steam to Steam.