Hi,
The site name and the welcome link are not in the breadcrumb. The breadcrumb is only the little breadcrumb part listing the sites path from the root to where you are at the moment.
You are probably trying to change the wrong object.
The welcome link is in the following control in the master page:
<td valign="middle" class="ms-globallinks">
<wssuc:Welcome id="IdWelcome" runat="server" EnableViewState="false"></wssuc:Welcome>
</td>
And the site title is:
<h1 class="ms-sitetitle">
<SharePoint:SPLinkButton runat="server" NavigateUrl="~site/" id="onetidProjectPropertyTitle">
<SharePoint:ProjectProperty Property="Title" runat="server" />
</SharePoint:SPLinkButton>
</h1>
Hope this helps.
Mirjam
www.sharepointblogs.com/mirjam