Dan,
Sausage rusk is a yeastless product and denser that the one in your picture, we have similar products in the UK, I doubt it will hold as much water as sausage rusk.
Sausage rusk is a basic biscuit/cookie dough without egg,sugar or butter.
It's rolled flat then baked slowly until it's half done then sliced in half, turned over and finish baked. Then ground to the right size.
Here's a commercial product spec
http://www.scobiesdirect.com/PDF%20Spec ... 1KE005.pdf
Oh and it's not toasted either
LD