Thrifty - Returning vehicle prior to facility open time?

I've got a pretty schweet rate booked for a mid-size in SJU next week. I am scheduled for a 6:00 am return. Have come to find that my airline has rescheduled my departure time to 6:30 which would require me to be at SJU (most likely) NLT 5:45. The Thrifty facility at SJU apparently does not open until 6:00 am. Can I leave the car at the facility prior to 6:00 am? Is there a way to get to the terminal?

I've got a pretty schweet rate booked for a mid-size in SJU next week. I am scheduled for a 6:00 am return. Have come to find that my airline has rescheduled my departure time to 6:30 which would require me to be at SJU (most likely) NLT 5:45. The Thrifty facility at SJU apparently does not open until 6:00 am. Can I leave the car at the facility prior to 6:00 am? Is there a way to get to the terminal?
When I was there in December or 2006, the Thrifty location was a good bit away from the airport.

However, I notice this now in their reservation terms and conditions:

Rental counter is located in Airport Terminal near baggage claim. After signing the rental agreement, the customer will be shuttled to the car parking area. * Phone Number - (787) 253-2525

Sounds like they may have opened an in-terminal counter [or it could have been there when I was there but it was unstaffed], but the cars are still offsite (probably in the same place they were back then).

It's not easy distance by any means--it was probably close to 10 minutes by shuttle bus (if my memory is correct, see this Google map (http://maps.google.com/maps?f=d&source=s_d&saddr=SJU&daddr=Cll+Marginal&hl=en&geocode=FWtRGQEdwdcQ_ClP1VWK0mUDjDGgyd01b8-rnQ%3BFXI-GQEdhuAQ_A&mra=cc&sll=18.422605,-66.00939&sspn=0.034283,0.066047&ie=UTF8&t=h&z=15)--could also be one of the other rental car-looking places to the east of that point), and I don't know that there's any easy pedestrian access other than on the side of the road.

I'd suggest calling the number provided above and asking how you should handle this. They may have some special arrangement to leave the car in the airport parking garage or something (I've seen that done at other locations).