Mobile,
I think you may be mixing up trade mark protection and design protection. Although there is some overlap in the protection of both concepts, trade mark law is designed to protect brands (badges of trade origin) and designs the look of a product.
You can register the image of the box as a trade mark, but thats what it would protect the image of the box, not the box itself. If the OP never used the image as a trade mark and never intended to use the image then the registration would be invalid. Design protection is the best form of protection if you are looking to protect the look of the box. 3D shape marks can be registered as a trade marks (I have successfully prosecuted them through to grant), but they are very hard to register and generally only shape marks which are very well known and the public see the shape (not any added words) as a trade mark can be registered e.g. the Coca Cola bottle.
One thing the OP must bear in mind, you have one year form first marketing/public disclosure of the design to register it, once that time period is up any design application you file will be invalid. Remember remember that time period!
Also think about where the product will be manufactured, as well as where it will be sold. We have clients who do not sell their product in China, but manufacture it there, so we have registered the design of the product there, as well as any associated brands as trade marks before the Chinese IP Office, as well as the states e.g. the the UK or via Community Trade Mark Applications across the whole EU where they sell their products.
I suggest you go to a fully qualified trade mark or patent attorney firm for some initial advice. Some links below:-
http://www.itma.org.uk/links#members-services
Maybe find a local firm and they will usually give you some initial free advice.
If you have a brand to market your box then this should be registered as a trade mark.