BL2600 I2C pins information needed.

Hello,
I'm new BL2600 user and I cannot find information where to connect I2C lines. I tried PortF by changing i2c.lib a little and I was able to use pins 20 and 21 but voltage level varies only 4.7 V to 2.5 V and instead of 0-5 V . I tried several different pullup resistors but still  the source voltage won't go to zero.
Are there any information how ports are mapped to BL2600 pins ? I can find RCM3000 port diagrams but there are no such information for BL2600. For example what is the port connected to pins DIN24-DIN32 and can I use those pins to I2c ?


Any help would be greatly appreciated.