Changing the height of a CHeaderCtrl that a CListCtrl uses

Does anyone know what mechanism a CListCtrl uses to determine where it can start drawing if you are using it in a Report mode with column headers?
I've have been using Spy++ to see what messages the CHeaderCtrl gets, but I cannot figure out what the CListCtrl is doing. I tried trapping the
HDM_LAYOUT message in the CHeaderCtrls DefWindowProc( I subclassed the header ), and from what I can tell the HDM_LAYOUT is being handled,
but when I try to change the cy value in the HD_LAYOUT under the WINDOWPOS.cy nothing happens. Any help would be greatly appreciated.

Sorry about the anon. post but the board won't recognize my password or something.
TIA,

Dan Ramage

[real name]

just now i have first half-success with this source
half because i wand header smaller and first list ctrl line does not move up from original position (testing with xp look)

HRESULT CHeaderCtrlSmall::GetLayout(WPARAM wParam, LPARAM lParam)
{
HD_LAYOUT *phdLayout;
RECT *pRc;
WINDOWPOS *pWPos;

phdLayout = (HD_LAYOUT*)lParam;
pRc = phdLayout->prc;
pWPos = phdLayout->pwpos;

HRESULT lResult = CHeaderCtrl::DefWindowProc(HDM_LAYOUT, wParam, lParam);

int bottom_old = pRc->bottom;
pRc->bottom = 25;
pWPos->cy -= bottom_old - pRc->bottom;
lResult = S_OK;

return lResult;
}