I just assumed that it came as a kit with the cargo net. So I take it that you ordered the part from your dealer and it didn't come with these hooks? I'm interested because I was just about to do this mod myself.
I ordered the cargo net kit (OEM Part: F5510FS000 $21.42) from subaruparts.com
They sent me the F5510FS000 kit, but it's different than what everyone else appears to get when they order the kit. Instead on "T" hooks, my kit came with a "strap". Basically my kit doesn't have the correct hardware. I'm going to hit up my local Subaru dealer to get the right pieces. The cargo net looks sweet and is functional, I can't wait to get it installed.
I ordered the cargo net kit from subaruparts.com, it was less than $25.00 shipped (and arrived in 3 days). Your local Subaru dealer can get it to I'm sure, you might be better of going local (incase the parts are wrong like with mine).