Yes you can code your key so it doesn't beep. NCS Expert is your friend. Search here or at bmwcoding to see how its done.
Silver 2004 BMW E66 / 745Li (DIYs):
ASK, Logic 7, blower, battery, guibo joint, active stabilizer bar bushings, diff oil, tranny sw update, vacuum pump gasket, window lift, a/c compressor, washer fluid reservoir, belt tensioner and deflector, crankcase vacuum hoses, crankcase vents, solenoid gaskets, headlight overhaul, ISM, hood lifts, driver mirror, sway bar end links, rear fog lamps, headlight washer, headlight vertical aim, VCGs
next up: P0492