For NFD, pos is called "forging." You need to download the NFD client, get it up and running, get some NFD from Bter, withdraw your NFD to your wallet, wait for 1,440 confirmations after your withdrawal, and then you can pos through forging. In my experience, 5 million NFD - 0.1 BTC's worth at the ask - is enough to get you some blocks. Right now, 1,440 confirmations takes about a day and a half.
There's even a special Asset called NSC, "Network Security Coin," which rewards forgers. It's given away by the tech lead MaWo once every week to forgers who forge blocks. The NFD bounty account has a buywall for it. So, you can forge, get NSC for the blocks you forge, and sell them into the bounty account buywall. That's how pos works in NFD.
If you're interested: click "Asset Exchange" in your NFD wallet, look for the "Add Asset" button in the top right area, click it, and clipboard this number into the form: 8537833860395844488 You'll see the orderbook appear, which includes the bounty-account buywall.
The original announcement for NSC is here: https://bitcointalksearch.org/topic/m.8852588
Thanks for asking!