Martin,
The older 45 CTL-4 was updated to digital which is still current. Main visible diference appears to be the addition of a little digital ' mode ' info window on the back panel. No doubt inside there are some additional electronics. If yours is the non digital version then in the Canon era we are talking film cameras like the T90 and T60, with very basic by todays standards, TTL systems. Link to T90
http://www.mir.com.my/rb/photography...nt90/index.htm
I have had a look on Mecablitz web site Link
http://www.metz.de/en/photo_electron...blitz.138.html
SCA 3102 appears to be the correct SCA adaptor but the hint to your probs may be in the cable to connect that to the flashgun itself - Connection cable SCA 3045 is mentioned as a requirement for the 45 CTL4 digital. Not sure that the pre digital version will have all the necessary connections for the SCA 3045 cable.
The manual is available here link
http://www.metz.de/en/photo_electron...nuals.164.html
I have the 45 CL-3, but have only ever used it in manual mode or auto ( standard sync cable or slave ), so have never gone down the SCA adaptor route to have first hand knowledge of the various adaptors and cables.
Hope this is of some help.
Don