The easiest way to do what you want without making a change in your docking is to get one of those short usb standard jack to standard socket. They are like a little extension that mainly come bundled with thumbdrives so they are easy to connect to crammed USB ports. You can open that extension (don't snip it) along the cable to exposed d the inside conductor wires. You will have 5 conductors, the shield (either a silver braided sleeve or a plastic like silver sleeve), red (+5), black (volt gnd), green (-data) and white (+data) (sometimes they replace the white for yellow). After exposing the conductors peel a little bit of the two data cables, short them together (don't snip them), put some black electrical tape around them to shield them then do the same for the larger cut you did. When you connect this cable to your charger then to the docking the two data cables short will signal the phone to go on fast charging. Make sure you do have a charger rated for at least 1.5 amps. Don't use this cable if you are doing anything that requires communication with the phone as this will not allow any data to flow to the phone. Use only when fast charging is required.
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Early 90's Motorola Brick phone -> Smaller Motorola -> Early 2000's Ericson -> Nokia -> Blackberry 7290 -> Blackberry 9000 (Bold) -> Blackberry 9800 (Torch) -> Galaxy I717 (Note)