I've seen a thread on POTN initiated by TMR design that demonstated how to calibrate your L-758DR using a Sekonic calibration target and the software that is included with the meter. The process seemed to be cumbersome and prone to error which is why TMR Design came up with his thread in the first place. Trying to calibrate the meter just using the software and the manual seemed like a very hit and miss proposition.
There is now a video located on the sekonic website that shows how to calibrate the L-758DR in an easy to follow demonstration.
I now have a reason to buy the sekonic target and calibrate my 5D and MkIIn to my L-758DR and..; I hope watching this video will help others that desire this level of accuracy in their equipment.