RenderElement file format settings

Hi,
I'm getting lot of problem getting correct settings for file format options when assigning renderelement path through maxscript.
exr and pnd settings are never set correctly (sometimes png 16bits, sometimes nothing check in png options, etc etc).
Anyone having a robust solution ?

basically :
renderSceneDialog.close()

-- render elements (png)
re = maxOps.GetCurRenderElementMgr()
nbrREs = re.numrenderelements()
re.SetElementsActive true

for i=0 to (nbrREs-1) do
(
el = re.GetRenderElement i
re.SetRenderElementFileName i ""
)
for i=0 to (nbrREs-1) do
(
el = re.GetRenderElement i
el.filterOn = true
el.enabled = true
elname = el.elementName

if (elname == "VRayZDepth") then
(
elname = "Z"
outputfilename = MattesPath + elname + "_.exr"
re.SetRenderElementFileName i ""

-- EXR interface settings
fopenexr.setLayerOutputFormat 0 1 -- 0:Full 1:Half 2:Integer
fopenexr.setLayerOutputType 0 1 -- 0:RGBA 1:RGB 2:Mono
fopenexr.SetCompression 2 -- 0:None 1:RLE 2:ZLIB(per scanline) 3:ZLIB(block of 16) 4:PIZ
fopenexr.setSaveScanline true -- false:tiles true:scanlines
fopenexr.setSaveRegion false -- false:full image true:region
re.SetRenderElementFileName i outputfilename
)

if (elname != "Z") then
(
outputfilename = MattesPath + elname + "_.png"
re.SetRenderElementFileName i ""

-- PNG interface settings
pngio.setType #true24
pngio.setAlpha false
pngio.setInterlaced false
re.SetRenderElementFileName i outputfilename
)
)
renderSceneDialog.update()