U need to find SATA to IDE 44 adapter like this:

2_5_39_39_Hard_Drive_SATA_to_IDE_44_Pin_Converter_Adapter_1455_6.jpg

I do the same, and MM have enough space inside for placing 2.5" SATA drive with adapter without cutting of everything. Only one moment - you need new hole(s) for new drive for fix it inside frame by screw. Also you can remove terrible speaker, you get more space for drive and can forget about "TADAAA" during each boot :)

[ Edited by clr666 30.01.2016 - 11:20 ]