Has anyone tried a roll with a Tower Hobbies 40 Trainer?

I'm starting to get a little more ambitious with my flying now I am comfortable with flying the approach pattern, taking off and landing, flying simple figure 8s etc.

I've pretty much got loops sorted, so I tried a roll the other day and had a 'OMG I'm gonna crash' moment! [X(]

I started going into a climb (I read the trainers will always end a roll heading towards the ground if you are not compensating with any elevator input) and close to full throttle. I then put in full right aileron and it S-L-O-W-L-Y started to roll - actually it was quick to get to about 90degrees to the ground, thats when it started to dive towards the ground. I kept in the full aileron and eventually it made it fully round, but I wasn't expecting the sudden drop and diving tendency.

If I put in some down elevator to compensate for the diving as it starts to get close to upside down will I be able to get it to roll smoother?