Attaching downspouts to "fake brick"

[Bananaosten]

Hello!

I have a facade made of "fusktegel" which I think is also called mexitegel.

It's a type of brick with a few holes, and it's also glossy and brittle.

I'm not quite sure how to attach the downpipes to this facade. What type of screw/plug to use.
Ordinary plugs probably won't work as the brick cracks relatively easily, making the drill hole too large.

Does anyone know?

Thanks in advance.

 

[Demmpa]

Drill into the mortar between the stones.

We have white mexitegel from the 70s, it is homogeneous throughout the stone.