How can I replace my Blaupunkt CC20 cassette player ?

I drive a Vauxhall Combo van with a Blaupunkt CC20 cassette player . I've got a Siemens CDR2005 CD player but the connections are all wrong . Can the CD player be re-wired to the existing wiring ? If so , any idea where I can get the relevant connectors ?
Or does anyone know a good radio engineer in the Luton area ??