so I am getting the feeling that POS is only for "selected" users with a special config file because in the basic (wallet installation + receiving coins) is not enough for getting POS working on this SIGIL wallet! And devs did not give us any config file, any other needs for enabling POS (min amount of coins in the wallet, min count of confirmations, min age) nothing...
You don't need a conf file, it's been working for everyone. Are you positive that you've waited 24 hours since your coins were confirmed in your wallet? If so, try closing/reopening it and see if it's fixed.
Can you open "Coin Control" and make sure you have separate transactions with more than 50 coins in them? If you're lacking this your coins won't stake either.