I had the same problem with breadcrumbs and cms pages a few days ago check here ->
Similar to Anders Rasmussen post I edited every cms page manually
In breadcrumbs.phtml I added a little condition to define if a Page is a CMS page (thanks to Alan Storm) and remove standard crumb(s) and added new crumbs via xmllayout.
<?php
if($this->getRequest()->getModuleName() == 'cms'){
unset($crumbs['cms_page']);
}
?>
xml:
<reference name="breadcrumbs">
<action method="addCrumb">
<crumbName>cms_page_1st_child</crumbName>
<crumbInfo><label>1st child</label><title>1st child</title><link>/1st child/</link></crumbInfo>
</action>
<action method="addCrumb">
<crumbName>cms_page_2nd_child</crumbName>
<crumbInfo><label>2nd child</label><title>2nd child</title></crumbInfo>
</action>
</reference>
hope that helps,
Rito