|What have they got against winzip (assuming that - as it's commercial use - you have paid for a licence)? It's not as if it's any sort of security risk, and a version bought from the publisher is going to be free of malware. You could make an .iso image of the folder, but they probably don't allow the software to do that.|
The real answer is to draw up a document outlining the business case for this and give it to your manager. Ask him to talk to the IT manager to ensure that they get their priorities right and support business needs rather than just policing for the sake of it.