I have to agree with Juliet. Solomon did not write it, he never existed. He was a story, written by (if memory grants me) various artists and writers. Solomon in the bible, Solomon in Ethiopian texts, Solomon in the Persian stories. Never existed, I have been into Solomonic magick for some time now and even though Solomon never wrote it, the one who did was truly a Solomon of his own. My perception of "Solomon" is that it is a title, a state of being. Like how in the forum there is Beginner, Novice, Knowledgable, Adept. Solomon is the adept. The temple of Solomon was never found and never existed. The time when his great temple was built, was the time when Nebuchadnezzar, where he reigned over. However this fact, of Solomon's non-existance is not to taint the ingenuity of the "Key of Solomon" Indeed, it is true and it is very effective.
I have been into Ceremonial magick and hopefully Solomonic magick to conclude (for myself) that those invocations and those holy names or rather Barbarous names are only words that stimulate the mind so that the practitioner believes he is in control of all things. It is all in your mind. The circle, filled with various sigils stimulate the subconscious mind so that it activates a certain portion of the brain. As Crowley has stated in "The Equinox" It is all about Mnemonics. The secret to Kabbalistic Correspondences, like the incense, color, number of candles, God names, are all mnemonics. They were carefully chosen and tested so that when you smell that incense then your subconscious mind is influenced of mercury, when you see that color your subconscious mind is stimulated for mercury,etc.
Those demons, are not actually based on the Christian perception. They are not from hell (or if you believe that your subconscious mind is hell then you are right.) You are summoning portions of your mind that correspond to the task. Did you ever wonder why YOU had to stare into the demon's sigil and not face it outward to a particular direction? It is because looking at that symbol stimulates a portion of the mind through visual stimulation. It is like getting goosebumps when hearing a chalkboard being scratched, it's an involuntary action.
When summoning demons, you are not actually summoning something outside yourself or are you? "As above so below, as within so without" says the Great Hermes Trismegistus in the emerald tablet. You are summoning something that is within you, therefore if one wants the secrets to invisibility, one would have to summon "Bael" which is the demon or rather portion of the mind that corresponds to that action. Think of it as a method of self-improvement, or Psychotherapy, except it reflects to the world around you, "As above so below, as within so without"
However, when summoning, one should maintain the medieval mindset. To make it most effective is to actually believe you are Solomon, the demon is not a portion of the mind but a Real demon from hell, etc. It will do wonders. I hope this helped in some ways. 93!