It appears to be a rather odd connector you have there. Although it very much resembles a standard 8-Way square connector, (and it's not a 4-Pin connector BTW,) the offset depth between the two rows of terminals throws it off a bit from the standard ones that I've seen, (see first link below.). But, in any case what you will need to tow the Casita is a Bargman 7-Pin round trailer connector to mate up with the Casita plug. Also, just FYI, a standard 4-Pin "flat" connector won't work because the Casitas have electric brakes and a battery charging hot leg as well, which the 4-Pin connectors can't accommodate. The one you need is in the second and third links below.
And if you want to also hook up your reverse lights to work on the trailer, the reverse light wire needs to be attached to the center pin, marked "Accessory," in the plug wiring schematic, (from your tow vehicle's reverse light wire.) The Casita's reverse lights are already hooked up at the factory to the umbilical on that center pin of the plug.
Edited by Euphoria, 30 November 2018 - 07:37 AM.