If the web interface is similar to my Linkstation live, you can see what kind of HDD you have inside.
Go to "System Status" then "Drive properties".
You can see the unit name. If the name is ST31000340AS or similar, you've got Seagate HDD inside.
Tell me what's the result, I'm curious :)
you're luckier than me, My two fisrt Linsktation had Seagate inside. The first is dead two days after I buy it. :(