Problems rendering tiles in UTM projection

Hello all,
I am using mapnik to generate local maps. This works fine for the 'normal' projections, such as 900913.
But when rendering tiles in UTM, i face strange behaviors: the map seems to break some regions (see attached image). I have already searched and found the description of similar problems for UTM rendering, but following the instructions (setting the extent Paramter) did not really help.
These errors only occur when rendering tiles (using the generate_tiles.py script); generating a single image (generate_image.py) works fine...
Am I missing the point?


As you see, some tiles seem to be shifted (like the "da" in "Drogheda")

This is what we did:

1. setup under windows: complete from the scratch, incl. PostgreSQL 9.1, PostGIS 1.5, Python 2.7, proj4
2. Mapnik: installed version 2.0.1.RC0, mapnik python from http://svn.openstreetmap.org/applications/rendering/mapnik/
3. Data loaded into DB using osm2pgsql with the -E 2157 option (UTM zone for Ireland)
4. Changes in configuration:
1. osm.xml, changed to (the string was provided by http://spatialreference.org/ref/epsg/2157/):

   <Map background-color="#b5d0d0" srs="+proj=tmerc +lat_0=53.5 +lon_0=-8 +k=0.99982 +x_0=600000 +y_0=750000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs" minimum-version="2.0.0">

2. datasource-settings.xml.inc: Projected Bounds from website ->

   <Parameter name="extent">418829.9650, 511786.6808, 786046.9273, 964701.5937</Parameter>
   

3. settings.xml: changed the referenced osm2pgsql_projection:

   <!ENTITY osm2pgsql_projection "+proj=tmerc +lat_0=53.5 +lon_0=-8 +k=0.99982 +x_0=600000 +y_0=750000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs">
   

4. generate_tiles.py:

   bbox = (-10.6000, 51.3300, -5.3300, 55.4000)
   

This little error troubles me now for some days; it is really frustrating, has anyone an idea of how to proceed? Is the patch mentioned in this message already part of mapnik_2.0.1.RC0?

Kind regards, Dieter