wiring new honeywell thermosta

I am trying to wire up my new thermostat. The old system has an 8 wire lead-no problem. But I have the following wires:
X
G
Y
O
B
W2
E
R

The problem is the terminals that are on my new RTH7600D Honeywell are as follows.
C
G
Y
O/B
RC
R
AUX
E
L

I have questions to where to connect the B & X wires.......HELP!!!