Brazing aluminium & steel

I want to extend my computer hard disk drive hanger with some aluminium plates - they're meant to screw on but if you do that then the computer's metal case doesn't close properly because of the extra width of the newly merged assembly. I hit upon the idea of brazing the thing together - anyone know how its done? Will a handheld blowtorch reach sufficient temperature? What weight will hang from the join? Is there a convenient directory of people who undertakes jobs like this? Yellow pages doesn't seem much good from what I can see