This quote is from the Curt 19100 "bumper hitch":
"***DO NOT EXCEED VEHICLE MANUFACTURER'S RECOMMENDED TOWING CAPACITY.***
WARNING: ALL NON-TRAILER LOADS APPLIED TO THIS PRODUCT MUST BE SUPPORTED BY 18050 STABILIZING STRAPS
HAVING INSTALLATION QUESTIONS? CALL TECHNICAL SUPPORT AT 1-800-798-0813"
http://www.curtmfg.com/part/19100 If you compare the Curt hitch to the one in your picture, you'll see that the Curt model appears to be a more "robust" type hitch, but I don't know if it's actually stronger or built better, just the appearance looks better....
A couple of comments, first, Keystone doesn't post a "recommended towing capacity' so there's no way to know if you're exceeding it or not. Same with Lippert, who manufactures the actual trailer chassis.
Second, using a "cargo carrier" is a "non-trailer load" and would require "supporting/stabilizing straps. I'm not sure, with your configuration, where you'd attach the support straps to the cargo carrier/bumper hitch assembly.
You might want to call Curt at the number in the above quote and discuss your ideas with them. They may "give you blessings" or they may urge you not to use that type hitch on a Lippert bumper.... If you do contact them, would you please share their comments with the forum?