See thread
https://www.pentaxforums.com/forums/camera-studio-accessories/62768-metz-58-hss.html — there's a bug in the Metz 58 AF-1 firmware which prevents it working in high-speed sync mode as a wireless controller.
When I had my Sigma EF530DG Super, I had trouble getting it to work in HSS mode (which they call "FP") at all, but I may have been doing something wrong. I also didn't have a second flash to test with. Can someone who does verify that it (as the manual implies) work just fine in HSS mode as both wireless slave and controller?
Thanks.