The router and powerline device should be connected by cable.
It seems that you didn't realize that we can also connect to WPA4220 by wire to access internet.

I have it set up by wire right now. I'll explain my situation in more detail.

I have two clients in a different building than the internet router that requires internet access.
I could not get any signal at all using only 2 units, one client side and one router side. I did however get a signal between building 2 and 3, and building 1 and 2.
I tried plugging two additional units into a dual socket in building 2 and linking them with an ethernet cable and voila, I got signal the whole way.
The problem is I can't get a signal to a wall socket near the router, the way everything is set up now is very temporary and I would like to get rid of the cable between the router and unit 1.
There are no walls between the location of unit 1 and the router, so a wireless solution should be fine, if there is one available.


Building 1 Building 2
######################## ########################
#unit 1) # # #
# ) # # #
# ) # #unit 2) #
#router) # - 30m - # unit 3) #
######################## ########################
|
|
150m
| Building 3
########################
# #
#unit 4) #
#clients) #
# #
# #
########################

Correction:
[CODE]Building 1 Building 2
######################## ########################
#unit 1) # # #
# ) # # #
# ) # #unit 2) #
#router) # - 30m - #unit 3) #
######################## ########################
|
|
150m
| Building 3
########################
# #
#unit 4) #
#clients) #
# #
# #
########################[/CODE]


It looks like the TL-WPA4220 unit doesn't have the bridge function that converts wireless to wired. I think the best thing to do is get a WiFi range extender that has an ethernet port such as the TL-WA750RE or use a router in bridge mode.