[OpenLayers-Users] Openlayers - tilecache and overlay problem

[Vincent Picavet]

Hello,
Here is my setup :
* mapserver serving a WMS layer
* Tilecache caching this layer (same host)
* Openlayers as a client

I set up Openlayers to display the layer as WMS directly from mapserver, it 
works well. Then I set it up to display the same layer from tilecache, and it 
works like a charm.

The thing is that I would like to have this layer as a transparent overlay in 
openlayers. When I enable the transparency (transparent: "true" in layer 
creation), the WMS appears as an overlay. Everything fine up to here.
But when I do the same with WMSC from tilecache, and check the corresponding 
layer in openlayer's overlay list, I only have broken images. Same result if 
I create the WMS layer without transparency, and try this just after 
creation :
wmsc_layer.setIsBaseLayer(false);

The trouble seems to be on openlayer's side, but I can't figure out why it 
can't find tilecache images when the layer is in overlay mode, whereas it can 
find them in BaseLayer mode.
Any idea ?

And last but not least : thanks for those tools, great pieces of software !
Vincent