VLTOR MUR ejection port cover???

I'm currently doing a build using a VLTOR MUR upper; since I'm starting from scratch I figured I'd change the ejection port cover with an engraved one just for fun. I've learned that you need to remove the forward assist / deflector module that is pinned on and install the cover from the back side.

At least this is how I think it is done..............Is there anyone who can clarify this for me, as to how to do it, or anyone who has a step by step guide/or any pics. (I may be asking for a bit much with the guide part but figured what the hell :D )

Below is the link for all I was able to find on the matter:

https://www.m4carbine.net/showthread.php?t=54392

Thanks for your help

Basically it'll have to go back to VLTOR for swapping out the dust door on VLTOR upper.