Yes you do, you have a cylinder. Move it up on the cam band (i.e. move
the BCD Down) and you move your centre of gravity upwards which should
help the problem.

Pete
diving 'at' melbourne 'dot' me 'dot' uk

There are several options.  When you have no weights, it's not as easy as
when you do.

For the Pool:
Try moving your tank up or down in your BCD.  Sometimes a little adjustment
can make a noticable difference.
Try moving anything that is positive, down and anything that is negative,
up.  My knife and my backup dive lights are negative.  My primary dive light
is buoyant.
Try different fins.  Some are more or less buoyuant than others.
Try different booties (assumes you are nor wearing a drysuit), some are more
buoyant than others..

For the Ocean:
Find somebody with a plate and wing setup and see if they'll let you give it
a try.  The plate tends to make a more balanced trim easy by moving weight
from the waist to the center of buoyancy, near the lungs.  Plates are
available in both stainless (relatively heavy) and aluminum (relatively
light).  The wing also helps.  A jacket style BCD tends to pull you head up
because the air cells are high.  Some wings have circular air chambers which
don't tend to pull you in a particular direction as much.
If a plate is not an option, or does not provide the desired effect (I think
it will), try moving weights.  Depending on your configuration, you may find
that you can safely dive with some fixed weight.  If so, you can move it
around pretty easily, to shoulder straps, tank straps, around the valve,
whatever it takes to make yo umost comfortable.
Try different fins.   <grin>   Try Mares.

Lee