Hi,

I haven't used Solidworks for some time but it should be as simple as it is in Solidedge and Inventor.

Solidedge calls it 'replace part and Inventor calls it 'replace component'.

Once you have imported the STEP file into the program, you save that. So, if you have one hundred M5 screws in the assembly (it will have named them M5 Screw_1, M5 Screw_2 and so on or something like it), then select the 99 screws after M5 Screw_1 and it should be as simple as RMB and replace part (using the M5 Screw_1 as the part to replace with). As all the screws are the same, they should all be orientated the correct way when replaced. And resave again.

Hope that helps.