I think the problem is here:
installation:map[method:network repository:]You need to have some value for the var "repository"
After some digging in internet, XAPI code (because why not), I found the solution in an old commit in the XO repo:
https://github.com/vatesfr/xen-orchestra/commit/07bf93e022a0026cacf28bf8797646361f7ea4a6
I think the var need to be set to "pxe"
(i'm doing some more digging)
julien-f committed to vatesfr/xen-orchestra
Add PXE installation method for HVM templates. (fix #436)