Manipulating the cannons in Castrum Meridianum with a controller?

I'm hoping that someone can help with this as I felt useless during the cannon fights over the weekend with my first runs through CM. I highlight the cannon, press the button to interact, which brings up a special interaction bar. This bar has one command. I press the right trigger, which highlights that section of the bar. I press the special button, which brings up a circle indicator. I use the right stick to move the circle (which was a horrible idea... it should be the left stick since my right hand is already manipulating the trigger and action button). I can get the circle to turn orange, but pressing the action button again does nothing. There is an indication that the correct button is being pressed, but the GCD never happens and I just sit there, being a total waste of space.

Any ideas?

*headscratch*

you just made me realize it's already been what, two months, since I've run a CM?

If I recall correctly, it's click on the Cannon (X) (This causes your hotbar to change, and you have one action)
Perform the action (R2 + Circle I think, but if you can't do this, stop playing lol coz it is the regular hotbar)
This is where the circle comes up, cursor over the boss.
I'm fairly certain it's (X) To confirm, you fire and then go reload the cannon . . .

And I use reversed camera (like it was in FFXI), so it took me sometime to get used to reversed aiming with the canon... up is down and lef is right... If they used analog on ur left side this wouldnt be a problem , since i only have my camera reversed...

After you get the target where you want it you simply press "X" to fire. Since you already used the "action" to bring up the target in the first place. If you hit the action after you have the target out it would just reset the whole thing. so basically:

1. Target Canon
2. Hit Action Bar (R2 + X)
3. Move Circle Where You Want It
4. Hit "X" by itself (do not use R2/L2 like you would for an action)
5. Explosion, repeat from step 1

Maybe that was my issue. I was trying to shoot it while holding down the right trigger. I'll have to try to just press the button next time I have the targeting circle on the ground.

Aha!
yeah just Press X!