Problems persisting dockable form layout in the Delphi IDE

Question

I've written a small IDE extension for Delphi. My form descends from TDockableToolbarForm. I've figured out how to get the IDE to save the form's position in the .dst and .dsk files.

The form's registration looks like this:

procedure Register;
begin
  RegisterFieldAddress('MyForm', @MyForm);
  RegisterDesktopFormClass(TMyForm, 'My Form', 'MyForm');
  MyForm := TMyForm.Create(nil);
  MyForm.Show;
end;

and I added the following OnCreate handler to the form:

procedure TMyForm.FormCreate(Sender: TObject);
begin
  inherited;
  AutoSave :=True;
  SaveStateNecessary := True;
  DeskSection := 'My Form';
end;

This caused the following to be written to the dst/dsk files:

[My Form]
PercentageSizes=1
Create=1
Visible=0
Docked=1
State=0
Left=0
Top=0
Width=1193
Height=4115
MaxLeft=-1
MaxTop=-1
ClientWidth=1109
ClientHeight=3788
TBDockHeight=4115
LRDockWidth=1193
Dockable=1
StayOnTop=0

This allows the form's layout to persist between one run of the IDE and the next. However I'm having two problems:

1. When the package is first registered with the IDE I'd like the form to be docked on the left side by default (assuming the user isn't using the 'Classic Undocked' layout). Right now it's simply showing the form undocked.
2. When the package is uninstalled/reinstalled the form isn't using the previously saved layout settings. It again appears undocked.

I suspect both problems are cause by a missed step but I'm at a loss as to what that step is.

For the first problem I found TControl.ManualDock mentioned quite often in discussions about docking but it was always in reference to applications for which you have access to the source. I have no idea how to retrieve the necessary parameters from the IDE to call it.

For the second problem the only thing I know for sure is that the settings in the dst file are still present after the package has been uninstalled so I would think reinstalling the package would simple using the existing settings but that doesn't appear to be the case.