Publishing 32bit Applications - Remote Apps 2012 R2

Hi Guys,

I have 1 gateway server and 3 host servers.

Gateway = 2012 R2
2 x hosts = 2012 R2
1 x host = 2008 R2

I've logged onto the gateway, added all 3 host servers in remote desktop services, then when I go to publish an app from the 2008 R2 server (add then UNC to 2008 R2 box), it shoots out an error saying it can only be published from one of the 2012 R2 boxes. How can I get it to publish an application from the 2008 R2 box?

I have two 32bit applications that cant be installed on the 2012 R2 box due to compatibility issues so I installed it on another 2008 R2 box. Just need to now publish it.

UPDATE: I managed to create a RemoteApp .rdp file that loads into the 2008 R2 box and publishes the application. I can run it on the 2012 R2 box itself and my windows 7 box but how do we publish this .rdp file in the remote app portal?

thanks in advance!