Erase texture regions

Hello everyone.
I’m triyng to draw something with the UV/Image editor, but I can’t see any way to delete part of my texture (ie not changing it to black, but actually erasing and/or make it transparent somewhere).

Is there any way to do so?

I did also look at the manual, but this specific issue isn’t addressed.

Thanks to anyone who will help me.

Bye, Ivano.

P.S.: Ignore this later message, it’s just to subscribe to the topic (which I didn’t previously).

set blend mode of your brush to ‘erase alpha’

Shame on me! Was that so simple, I didn’t neither try…
Thanks a lot.

Excuse me sir, I really don’t want to annoy, but please, can you tell me if there’s some method to select?
I just tried to hit “b” to be honest, but I see this won’t work. Are there any selection tools available?

Excuse me for such stupid question, maybe (again) the solution is just below my nose and I just can’t see it.

Thanks again.

Edit: Almost got it, I thought about a workaround: 1st, import the image as reference, 2nd use the reference to draw a nurbs/curve object which will be the selected region, 3rd UVMap it and match the reference to the same texture.
This way I should obtain a nurbs/curve textured object which just uses the portion I’m interested to.
Then, either with render layers and/or with compositing nodes, do whatever you want with the image, after all just render the result to a new image.

The only problem I have is I don’t know how to unwrap a curve to UV.
I tried experimenting with the material, I get vertex coloring, but all the vertices are the same color, there’s no mapping. How can I do?

Drop this please, it’s already been discussed in another thread.