Here's how I do it:
I buy Litecoin with cash from someone I know. Then I deposit the Litecoin using OpenLedger. In OpenLedger (or BitShares app) go to the exchange for the BTS:LTC trading pair. See the picture and note the place where it says Deposit Open.LTC
Click on that and send your LTC to OpenLedger. Once it is there (and it does take a few minutes for it to show up), you can then make trades or buy orders with LTC to buy BitShares.
Note: You can also do the same thing with Steem and Steem Backed Dollars (SBD) and send them directly from Steemit to OpenLedger. It works great!