Lpc2000

I'm using the 48 pin LPC2102 and I'm having difficulty configuring 
P0.17 and P0.18. I want to use these pins as a general purpose 
output to provide a high and low voltage without any pull ups, the 
problem is that on the board I'm using these pins appear only to be 
able to give me an open drain output. 

From the Pin Configuration section (Chapter 6) of the User Manual 
both P0.17 and P0.18 are indicated to be "5v tolerant pad providing 
digital I/O functions with TTL levels and hysteresis and 10ns Slew 
rate control" so it would seem that these pins can provide the 
required output. Now although I'm configuring the pins as GPIO I 
realise that these pins are shared with the I2C functionality, 
however for the other pins which can share both GPIO and I2C (P0.2 
and P0.3) it is explicitly stated in the manual that they are "open-
drain 5 V tolerant digital I/O I2C-bus 400Khz specification pad, it 
requires external pull-up to provide an Output functionality"

Is the manual wrong?, have I misunderstood? or do I need to 
configure something apart from the PINSEL0/PINSEL1? Any Ideas?