You don't explain why you're "splice the tps 5v reference wire" and I can't think of a good reason to do that. Can you elaborate?
Wire the boost solenoid to +12v (through a fuse, please!) and the second terminal to one of the high power outputs of the ECU (injector or coil are the best) and chose the output in "Outputs -> Assign Output Channels" Boost Control Channel entry.
In the Boost PID Settings, set Boost P, I, and D all to 0. Set Boost pwm max value to 95 or so. Boost pwm min value to 0. Check the help file (Press F1) if you want to know details of any of the settings.
Then set your Boost vs. RPM Curve as you wish your boost to be like.
Then set your refDC vs. Boost Target to get close to your RPM/Boost curves. Higher DC = higher boost. Try starting with around 20-30% and see where that puts you. Increase if it's lower than desired, decrease if boost is too high. Rinse and repeat. Once you have your base refDC pretty well sorted, you can go back and turn on PID if you wish to give you closed loop boost control.
If you don't ever want closed loop, you can use boost alternate, which is easier to set up, but open loop only. Just throwing it out there as an option. Boost control is really hard to explain without going into crazy amounts of detail. This should get you on the right track though.