In game store problem

Hi all, I have encountered an issue regarding creating an ingame store.

I use Json to store the information of players and create shoping but Windows phone doesn’t support ISerialzable while building.

Here is the error: System.Runtime.Serialization.SerializationInfo` doesn’t exist in target framework.

Has there been anyone who encountered this? or is there any other better way to create an ingame store.

Great many thanks

See:

for the classes that are supported on WP8.

Thank you very much