Good luck. This is basically impossible to do. The territorial range of the Clarion Angel are the Islas Revillagigedos (and specifically Isla Clarion from which the Angelfish gets its name), a group of islands a great distance from land in any direction.
(Wikipedia for the picture)
As you can see, swinging by the Islas Revillagigedos while you are in Mexico is like swinging by LA while you are in Houston.
The collection of this species by anyone has been severely limited for some time by the Mexican Government, and the entire fishery has been shut down recently I do believe. I think Steve Robinson has been talked about managing to get permission to reopen the fishery on a
very limited basis (and I bet he had to grease a lot of palms to do it).
The logistics of traveling the great distance to the natural territory of the fish to collect it, housing it on the return trip, and then shipping the fish are daunting (and incredibly expensive).
To further complicate matters, the US dollar is so weak, that almost none of the fish are being sent into the US and are instead being sent overseas where more money can be made.
If you want to give it a shot, remember that you will probably run into corruption within the Mexican government and even if you have the scratch to buy the permission to collect the fish, you will have to rent/buy a boat capable of a 1000 mile round trip and make sure that you have the ability to house the fish on your way back in.
Sorry, I didn't mean to rain on your parade. I think the fish is an absolutely gorgeous specimen and know that they are incredibly hardy and make great additions to an aquarium. I think I once read a Fenner article somewhere that called them the ideal aquarium inhabitant (if not for the hefty price tag).
If you manage to get a permit to export them, let me know. I would sell a kidney to get my hands on one someday.