pito,
I found my BMP085 and it seems to work with the Adafruit library by just changing Wire.h to TwiMaster.h.
I noticed this call in your post:
bmp.begin(I2C_100KHZ);
The argument should be a BMP085 mode, not an I2C speed. I don't know if that would make a difference.
I tested on an Uno and a 2560 Mega using the Adafruit example sketch. I don't have a 1284.