a question about filter diagnostics

Hi,

I defined a custom type and a conversion rule in order to test a simple filter 
script which only logs its parameters to "$TMPDIR/nullfilter.log" and doesn't 
produce any output. 
I can see my custom type being correctly identified in "error_log" but the 
filter script doesn't get mentioned in the log nor do the follow-up filters 
like "pstops". The FAQ is suggesting to set the "LogLevel" in cups.conf to 
"debug" but even with the setting "debug2" I'm not able to recognize what the 
missing part is.

Any suggestions as to why the filter isn't called up or how to further increase 
the diagnostic level? 

Cheers,
Cem Han

My config:
Debian 3.0
Cups 1.1.14

An extract from the generated log:

D [20/May/2003:16:29:07 +0300] StartJob: argv = 
"cp1","13","root","duplex06.ps","1","","/var/spool/cups/d00013-001"
D [20/May/2003:16:29:07 +0300] StartJob: env p"PATH=/usr/lib/cups/filter:.......
d [20/May/2003:16:29:07 +0300] StartJob: Allocating status buffer...
D [20/May/2003:16:29:07 +0300] StartJob: statusfds = 4, 5
D [20/May/2003:16:29:07 +0300] StartJob: filterfds[1] = 6, -1
D [20/May/2003:16:29:07 +0300] StartJob: backend = "/usr/lib/cups/backend/lpd"
D [20/May/2003:16:29:07 +0300] StartJob: filterfds[0] = -1, 7
D [20/May/2003:16:29:07 +0300] start_process("/usr/lib/cups/backend/lpd", 
bfff187c, bffecd2c, 6
, 7, 5)