[Tilecache] Transparent Layers w/ Tilecache

[Tom Farnham]

I'm running mapserver, OpenLayers and tilecache.

I'm attempting to create a map with a few overlays. I'm using  
tilecache as the middle man.

What's happening is when I make a layer transparent(read: overlay) in  
Open Layers it doesn't render via tilecache any more. If I make the  
layer normal with no transparency it works fine. Here's the url for  
the tile when it works fine:
http://taranis.unioncab.com/tilecache/tilecache.cgi?map=../Documents/ 
test.map&LAYERS=Posts&FORMAT=image% 
2Fgif&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&EXCEPTIONS=applic 
ation%2Fvnd.ogc.se_inimage&SRS=EPSG%3A4269&BBOX=-89.473485% 
2C43.060173%2C-89.385595%2C43.148063&WIDTH=256&HEIGHT=256

When I switch it to transparent it loads the pink tile instead. The  
url for that tile is:
http://taranis.unioncab.com/tilecache/tilecache.cgi?map=../Documents/ 
test.map&LAYERS=Posts&TRANSPARENT=true&FORMAT=image% 
2Fgif&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&EXCEPTIONS=applic 
ation%2Fvnd.ogc.se_inimage&SRS=EPSG%3A4269&BBOX=-89.473396% 
2C43.060294%2C-89.385505%2C43.148185&WIDTH=256&HEIGHT=256

I don't know why but Tilecache is shifting the bbox for each tile by  
just a little bit.

These images work fine when requested straight from the mapserv  
script. Any clue to why tilecache is shifting the transparent image a  
little bit?

Cooperatively,
tom