W211 replace Casette with CD Stereo

[JONDAV818]

Hi. I am looking for some advice which I am unable to find on here or the web.
I have purchased a w211 (2002) and it had a radio cassette fitted. I purchased a radio/cd from a 2005 w211 but the connections on the rear are totally different.
Can anybody offer me some advice as to whether I can purchase an adaptor or can it be hard wired etc... or is it useless to me.
The casette player I have is a CK1211 and the CD player I have purchased is an MF2321.
Thanks.

 

[JONDAV818]

I now understand the above but have encountered a different problem. If I was to remain using the cassette stereo but purchase the 6 cd changer for below. The cassette stereo has a cd button so believe it was designed for this purpose.
I have an empty cd tray at the bottom (A211 680 0552)which will take the cd changer but this tray is dated 31.03.07 and car is a 2002.
On the rear of the tray is a yellow cable which contains 2 yellow plugs and only 1 of these is unused(small plug).
To cut a long story short. Can I purchase any 6 cd changer and just slot it in. If I fail with this then I'll just purchase a japanese car 10 years older which will have a cd player. Thanks in advance and hope you can help.