If you don't want to wait on Coinomi you can always use the BCD Core wallet and import your keys there to claim your BCD.  That's what i did and it worked fine but it does require you to load the full 165GB blockchain.  You will want to send all your BTC to a new wallet first so you don't expose your BTC when you import the keys, i.e., make sure your wallet is empty of BTC before importing the keys somewhere else so you don't risk your BTC.  The BCD Core wallet is on github.  you can grab the compiled binaries here - https://github.com/eveybcd/BitcoinDiamond/releases.