How to create new termset using Client Object model

Hello

I want to add new term in Taxonomy term store programmatically using client object model and befoe adding new term I also like to validate that new term is exist or not, please let me know how can I do this?

I saw this url http://social.msdn.microsoft.com/Forums/en-US/sharepointgeneralprevious/thread/f71e147d-1235-49f9-bb61-521c4e4d73c2, where I understand how to add new term, but it does not give idea that how validate that new term is exist or not?

Please advise

Avian