Re: some general HW questions
You should try running the 1GB in DIMM1, then putting the two 256MB modules in DIMMs 2 and 4 to keep them on the same channel.
The contacts in SATA connectors are very small. I'm sure they are in there. I don't know of any motherboards that put in "mock" connectors. Either the motherboard has the connectors, or not.