This is a known bug in the Adafruit BMP085 library.
You can follow the discussion and the bug fix process in the Adafruit forum:
Raspberry Pi and the BMP085
GitHub issue: https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code/issues/38
Thanks for all suggestions!
UPDATE: Adafruit released a new official python library: https://github.com/adafruit/Adafruit_Python_BMP