Another Canning question?!

Another Canning question?

I can't find this anywhere on the web, and it's my first time canning. I got a couple packets that contain all the ingredients needed for canning salsa, all I have to add are the tomatoes and vinegar. My question is can I add some green peppers and cayenne to it also? I have a bunch from my garden, and the instructions don't say whether you can or can't add anything besides tomatoes and vinegar. I was just thinking that the acid count wouldn't be high enough if I added those extra ingredients, though I wouldn't be adding too much. Let me know all you expert canners, because I have no one to ask and like I said, it's my first year doing this.

THANKS for your patience!

Your salsa should be fine, even if you add a bit of improvisation. If you are truly concerned - a teaspoon of lemon juice will balance the acidity without compromising the flavor.