[Tilecache] Projecting with a different SRS

[Tyler Durden]

I've in my geoms fields(Postgis) in WSG84(EPSG:4326) and I want to
make the projection and generate the tiles with TileCache to World
Mercator(EPSG:3395), althougth I've srs=EPSG:3395 in my tilecache.cfg
it doesn't convert.
I'm using TileCache, OpenLayers and Mapnik. In my Mapnik osm.xml I've:
<Map bgcolor="&color_water;" srs="+proj=merc +k=1.0 +datum=WGS84 +over
+units=m">

This conversion is possible? Or I've must have the geoms in EPSG:3395?

Thanks,
Tyler