In the Examples folder you'll find the C-Store SCP example.
It's a console app.
In the OnReceiveAssocationRequest method you'll want to change the guard condition (line 60) - or just remove it entirely.
I had that very same sample code hooked up to a GE Ultrasound machine a couple of months ago.
Make sure you allow port 104 in your firewall. To simplify things, just use an IP address in the Ultrasound machine rather than trying to let it resolve DNS names (depending on how well the network is set up it can be hit & miss).
Let us know how you go :)