CICサイトにありますが、トピ主さんの場合、下記のUnless以下にある、違うカテゴリーのワークパーミット(オープンワーク→雇用者限定ワーク)での滞在延長にあたるので、Implied Statusが適用されず、働き続けることができないようです。
"I have applied for a new work permit. Can I stay in Canada if my work permit expires?"
Yes. You can stay in Canada, and may be able to keep working, under what's called implied status. That means the law implies you are a temporary resident. The implied status lasts until we decide on your new permit application. However, you must respect the following requirements:
If you applied for another work permit
-You must stay in Canada and meet the conditions of your original work permit. If you applied for a work permit extension before your work permit expired, you can keep working under the same conditions as your existing permit until we decide on your application unless you have applied to extend your stay under another category.
http://www.cic.gc.ca/english/helpcentre/answer.asp?qnum=188&top=17