After MSMS 3.5 is installed, you are able to upload and download files without them being scanned.

If debug logging is enabled, output similar to the following will be written to the sts2vsapi log:

19/04/16 19:43:35.453,17096,STS2Vsapi.cpp,1973,Instantiation completed at 993900437 with  ResltCode: 0x80070005
19/04/16 19:43:35.453,17096,STS2Vsapi.cpp,1976,CoCreateInstance on SPSHelper interface failed
19/04/16 19:43:35.453,17096,STS2Vsapi.cpp,681,80070005 returned by GetSPS2010Attributes(pilb, props,result)
19/04/16 19:43:35.453,17096,STS2Vsapi.cpp,684,CVirusScanner::Scan() - GetSPS2010Attributes() failed to retrive attributes mr=80070005
19/04/16 19:43:35.453,17096,STS2Vsapi.cpp,688,Exclusion List for User or For Site Found Returning from CVirusScanner::Scan() - OUT (Scan will be not performed)