location of the wastegate actuator on an SE

[vrmmmpshhh]

On the front of the turbo there should be a (gold??) round canister with a rod that runs to the back of the turbo. There should also be a vacuum hose going into that canister. I'm guessing the low mount SE makes it a bitch to get at.

[SalonRacing]

See pic, it will be hard to see if you have all the intake etc. hooked up.
I assume you want to put some kind of bleed valve in there to control boost?
If you still have all the factory stuff on your SE you will see the factory boost solenoid mounted to the front of the rocker cover you can intercept the wastegate vac line there. In fact you can mount your boost control to the same mount and just plug it into the vac lines, you will have to leave the factory solenoid plugged in or short the wires with a resistor so the ECU doesn't throw a fault code.

If you are not 100% sure that you are looking at the right thing you can try unplugging it and reading the fault code, then you will know you have the right thing.