The mode on the camera does not affect the physical properties of the lens. In whatever mode you're in, the minimum focus distance (distance from subject to sensor plane) is 1.1m. The maximum magnification is 0.31x - an insect 1 cm long will appear 0.31 cm long on the sensor, which translate to about 550 pixels across on a 450D.
What I'm trying to say is that nothing in the mode dial can make this lens focus closer than 1.1m.