The IR/RF assignment follows the device where the command actually exists. Therefore in your case the command you alias actually resides on Device2 which is RF Only the command will be sent out RF only. If you want to send it out IR, you would need another device assigned IR only and place the commands there, then alias them from wherever you want.

The beautiful thing about the MX-3000 is that you can create an IR only device with no ability to directly access the device itself, but you could just alias commands from other pages. making it relatively transparent.