Default [Q] How to buy themes on an incompatible device


this question might be a bit strange but here we go:

I want to be able to buy PA/CM11 themes on a device that has no theme engine. PlayStore (correctly) states "incompatible". However I want to pay with the (otherwise unused) money on the pre-paid SIM card in that device. Of course I have another device with PA but that device is on a mothly plan of another phone provider and it's a real hassle to switch SIM cards (N5 with tight-fitting case).

I know there are some apps that fake the device identification of the PlayStore but how to fake CM11-theme engine compatibility?