If your T4 is from your corporation, you will need a Letter of Reference from your corporation. Who will write the letter of reference, you? I'd say, even if "business owner and employee of own business," even if technically distinct from self-employed, would still be understood as self-employed, for that reason.
http://www.servicecanada.gc.ca/eng/ei/information/self_employed.shtml
Types of self-employment
The Income Tax Act of the CRA defines a business and other related arrangements. Here are some types of self-employment that are not usually insured under the EI Program.
A self-employed worker is an independent worker who contracts services to companies or individuals, controls his or her own working hours and usually does not own the business.
A sole owner directs all the activities of the business, assumes all authorities and obligations, and is personally liable for its business debts. A sole owner may hire someone to run the operation.
A partner pools resources with one or more people to operate a business for profit. Partners are jointly liable for the partnership's obligations and debts.
A co-adventurer in a business, regardless of the legal form of the business, has an interest in it with others and is involved personally in activities deemed necessary for its operation. It makes no difference whether the business is registered or incorporated. This interest in the business can take many forms, from money given or invested to an expectation of gaining from the profits.
In a corporation or limited company, a person who controls more than 40% of the voting shares is not necessarily self-employed, but is still considered uninsurable under the EI Act.
If you are not sure of your status as a self-employed person or if you need more information, you should contact your Service Canada Centre or the CRA .