Eclipse RCP IPageLayout woes

I have an Eclipse RCP application with a sort of three column layout:

The editor area is at the extreme right. Now, when you get an IPageLayout to work with, the editor area is already added in. That's fine: we add area B to the left of the editor, and area A to the left of B, and the layout is exactly what we need.

The issue is that when you move the sash between A and B, views A and B change without resizing the editor area (good;) but when you move the other sash between B and the editor area, all three views are resized; the layout manager acts to maintain the ratio of the widths of A and B, and that's not what we want. We want the user to be able to move each sash independently, and have it influence only the two views it touches.

It seems like the root cause of this is that the editor is in place when you get your IPageView, and therefore you have to position the IFolderLayouts relative to it. If you could position the editor relative to B, instead, then resize would do the right thing.

So my questions:

1. Is there any way to tell the IPageView to position the editor relative to a view, instead of the other way around?
2. Barring that, is there any other way to influence the layout algorithm, like writing some kind of layout manager?