[ODE] question about mass

[Hampus Soderstrom]

Hi,

If I have 1 unit in an ODE world represent 1 meter and I like to create a 
10 kg box with the size 1m*1m*1m, would I do like this (when setting 
mass):

dMassSetBoxTotal (&m, 10, 1,1,1);  //10 kg?
dBodySetMass(body[0], &m); //my box of size 1 1 1

When I run the simulation the box "feels" very heavy.. ie it falls through 
the ground. When I adjust the total mass to something lighter it bounces 
more correctly when falling down.

What would the correct relationship between kg and meters be?

regards

/Hampa