CT and BT toolholders

[crabbass]

I have a VF-3 with a CT 40 spindle.
I want to use a disc milling cutter made by seco. It is a metric size groove I am milling, and the 80mm dia *6mm disc milling cutter is perfect for my application. This cutter mounts to a shell mill holder, with a 22mm pilot and 10mm keys. Seco sent me a 22mm shell mill holder, with a din/iso taper. The toolchanger arm seems to fit the v groove fine. Is this perhaps a din/iso toolholder? ( BT tools have an offset groove, CT tools are centered). I want to use this holder, but cannot find a retention knob with a 16mm thread to match. Has anyone here ever ran any din/iso tools in their CT spindle machines?

[Haas_Apps]

DIN-69871 and ISO-7388 are the same as CAT other than the metric threads and a V notch on the flange.