breadcrumb issue after upgrading from vB3 to vB4

[Psalmist]

We're upgrading a large forum from vBulletin 3 to vBulletin 4.

In our vBulletin 3 setup, the forum is the home page, on the root of our site. Basically our whole site is the forum.

vBulletin 4 has an articles section and by default that's the home page. We followed instructions to make the forum the homepage in our vBulletin 4 test setup. But two problems remain, both related to the breadcrumb navigation.

1. In vBulletin 3, the leftmost breadcrumb is the site name, not "Forum". We want to keep it that way (it should be the site title, not "Forum").

2. Also, in vBulletin 3, there is no breadcrumb on the homepage. We also want to keep that the same. (In our current test setup of vBulletin 4, there's an unlinked "Forum" breadcrumb on the main page.)

Can you please advise.