Can I use playmoTV on my 3G/4G connection?
Due to the nature of how 3G connections work there is no possibility to change the DNS setting for out of the box the network connections via your cellular provider.
However, it works if you use another device (such as an iPhone) to connect via 3G and then use the iPhone to make a personal WiFi for the iPad. In that case, you just link the iPad to playmoTV like usually by changing the DNS settings for it.
Also, there are some applications on both iOS and Android that enable users to use custom DNS servers, but your mileage may vary using such apps.