Double-click the TOC (or paragraph, any other section) to highlight it in BD, then click the H2 (html fragment editor) button. Or open the fragment editor and check "whole code" and the entire book loads into the window as html.
Not to complicate matters, but obviously I don't do this manually for every TOC entry. What I do is to open the somebook.htm page in BD, which creates a Temp\tmp1\2\somebook.html0 page in the BookDesigner directory. Then I run a search-and-replace routine on this file
<DIV align=justify><A href= ==> <DIV align=left> <A href=
among many other cleanup replacements, to handle hanging dashes, quotemark widows, etc.
Then I load the html0 file into BD, do any "unique-to-this-book" modifications, and click Make.