I think you could set up two separate pick guards, one original and one Active, to meet your needs. What is it going to cost to do something like that? I use an Aguilar Tone Hammer and it is a pretty cool out board pre. Do you use a pedal board? If so, bend over make your change and back to it, never missing a beat. A better solution, however, considering what you are going to spend, might be to buy a Fender Deluxe PJ. Mexican made. Active electronics. Search for a good one and you're good to go for probably not much more than you would have spent...Good luck.
http://www.talkbass.com/forum/f126/f-s-fender-deluxe-active-p-bass-special-blizzard-pearl-1041974/
http://www.talkbass.com/forum/f126/f-s-fender-deluxe-active-p-bass-special-blizzard-pearl-1041974/