I don't get why it's such a dilemma. Working for 'da man' isn't fun when you're young and in a hurry. So much energy spent in trying to get what you want in an environment that is set up to quash all that. Even though they 'need' you, face it, they don't really need *you*. Give them enough grief, they'll remember it when you least want them to. Deception never works, you will get caught out.
The stories from other posters ought to be enough to say, be ethical and find a legal way, be it through ETFs, job reclassification, or properly set up trading outside of work that don't compromise your employment contract. Ultimately, if trading your own account is that important, it may mean even leaving corporate employment.
Kinda periferal to the subject, but why people still do 'non-work' trading or emailing from work also baffles me. It's the company equipment, time, and resources, so the idea that you (or anyone in such a situation) has some sort of "personal privacy" shouldn't even cross your mind. Get off the PC at work and do it at home or on a private PC offsite at lunchtime. The more you keep your private and corporate work lives separated, the better for your mental health. (I'm talking doing work at home or homework at work)