What version of Frontpage are you using? I'm guessing a pretty old one since it is called Expression Web in the newer versions. While I haven't used Expression Web I have heard it does better support current web design methodologies.
If you are using an old version of Frontpage, perhaps try out the newer version of Expression Web: http://www.microsoft.com/expression/
It is was just recently made freeware. However I don't know if Microsoft will be supporting the product going forward or not. But if you are still using Frontpage, your company probably doesn't care about that.
That way you are still using a WYSIWYG tool like the company wants and it will hopefully work with what you already have written.