www.edavs.com

I try to put http://my sever address:9000 or:2072 but can’t

You need to know the Qnap's description file address. you can test it in a browser firstly.

could you tell where can find the address?

Some Qnap use twonky as build-in media server.
you can try "http://IP Address:9000/TMSDeviceDescription.xml" in your PC's browser to test whether you can get a description file of your NAS.[IP Address is your NAS's]

when I use my ipad outside my house how can to use the airplayer to watch my NAS server?

Have you added it manually successfully?
if yes, when you outside the house，just use your NAS's public address.

admin wrote:Some Qnap use twonky as build-in media server.
you can try "http://IP Address:9000/TMSDeviceDescription.xml" in your PC's browser to test whether you can get a description file of your NAS.[IP Address is your NAS's]

I have Qnap TS-219P with built in Twonky.
Skip the TMS part in the link above and it should work.
Forward port 9000 in your router and then access Twonky in Air Player with this adress: "http://IP Address:9000/DeviceDescription.xml"
Works like a charm (when you have a decent internetconnection).