As long as the belt is in proper fore/aft alignment with the crankshaft and water pump pulleys, how it gets there is completely irrelevant. Just be sure there's enough contact around the circumference of the pulley to get enough belt traction to avoid slippage. It might be necessary to move the alternator a little further away from the engine than the generator was mounted to get enough belt contact with the pulley.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!