Crailberry

Hey all, I recently purchased the private military company expansion off of steam. I have arma 2 combined operations. As well as Dayz. When I launch PMC expansion directly from steam, nothing is different. I go into campaign and it just gives me the same options it's always given me. So then I go into Expansions in the main menu, and select the PMC expansion, I press "okay" to attempt to launch it, and it then says it needs to restart the game in order to apply any changes. So it restarts, but then nothing has changed. I still have the same campaign missions, nothing new! I think to myself that maybe now I need to go back into Expansions and click on the PMC expansion again now that it supposedly applied changes, but the same thing happens over and over again. I click "okay" and says it needs to restart to apply changes. So I can't figure out how to launch an expansion. Can anybody help? I've been searching through google and can't seem to find anything pertaining to my problem. Any help is greatly appreciated, thank you.