If what OP is requesting is against the company's IS / computer usage / IT policy then he is in for a world of hurt.
I worked for a company where someone, in IT, thought they had the right to circumvent these controls. The person was disciplined quicker than what you can minimise the browser window.
Most of the time, just add https :F
Also, I'm pretty much 99% sure I know where you work

(If you're in IT

)
The old https trick hardly works on config nowadays. If they implemented something like websense, then there's little luck of getting through.
OP,
please provide contact details for IT dept.
I could then advise them how to lock down each PC to the company site, and also lock down USB ports and DVD drive.
Then you're welcome to try tunnel firewall after that.
+1.
Lockdown all end points. Policies should restrict installation and configuration changes and external media (USB, cd/dvd, Bluetooth) should be restricted. Do a blanket statement like this on all endpoints and work with the exceptions afterwards. You'll find a lot of disgruntled employees that were violating policies and putting the company at risk.
If your company deals with client data and you are not on track to implement such controls (as example), you and the company are going to be in a rough spot when that client data is leaked.
I know there are a lot of companies out there that haven't considered POPI requirements and compliance at all.