Contact your county extension office, or get in touch with the National Center For Home Food Preservation, to get all your questions answered. Canning is an exact science. It requires precise timing (no guesswork), taking into account not only the ingredients in the recipe, but also altitude, and canning method. 15 min might be enough time, but you want to be absolutely certain. The jars will probably seal, but that may only indicate that enough air has been expelled to form a vacuum. It does not always mean that the contents have been processed long enough to eliminate any possibility of botulism, mold or other spoilage.
Another resource is Miss Vickie's Guide to Modern Pressure Cookery. This website has a forum where you can post your questions or concerns, and receive good answers. If Vickie Smith does not know the answer, she will point you toward the experts who can.
I hope you do well with your salsa. It sounds really good.
