Hey Christoph,
That customizing not seen in our SRM system too. After search , i saw that it is available after 713 sp 09. And my version is
Did you find any other way for that ?
SAP standard explanation note : 2202074 - IMG entry 'Define Task Types for Purchase Order Approval App' is missing
If you find another way , that will be helpful for us.
Regards,
Samet,