Ok... that post specifies:

"...CD behind Nav screen is only recognised if you have the BM54 New Generation radio fitted, if you have the BM24 fitted then you get the message "no tape" even though you have a cd fitted..."

I am assuming that means I have a BM24.. but I do not know how to tell.
Here is what is on mine:
Model#: C43 BM US
P/NO.: 65. 10-6 902 718
SW/NO: 42
Index: 06

Does that mean anything to any of you?