Can't overwrite a dvd+rw

[bergamote <bergamote@visitmail.com>]

Hi

First, my config:

kernel 2.6.7, PIONEER DVR-106D (firmware= 1.08)  and
* DVD±RW format utility by <appro@fy.chalmers.se>, version 4.8.

I have 2 problems:


1) I can't overwrite on a dvd+rw:
on a media out of the box, i can write and append data whithout problem.
But when i try to overwrite, i have this:

WARNING: /dev/scd1 already carries isofs!
About to execute 'mkisofs -R -J /home/bergamote/SNAP | builtin_dd 
of=/dev/scd1 obs=32k seek=0'
...
/dev/scd1: "Current Write Speed" is 2.0x1385KBps.
:-[ WRITE@LBA=0h failed with SK=5h/ASC=21h/ACQ=02h]: Invalid argument
:-( attempt to re-run with -dvd-compat -dvd-compat to engage DAO or 
apply full blanking procedure
:-( write failed: Invalid argument
[root@pogg]~$



Well, I don't want a DAO. so i try a blank.


2) After a blank (dvd+rw-format -blank /dev/scd1), the media seem to be 
exactely in the same state than when i have neve use it 
(dvd+rw-mediainfo says exactely the same things).
I can write data on, but growisofs -Z says that:
" /dev/scd1: FEATURE 21h is not on, engaging DAO... "

And of course, when i try a growisofs -M, i see:
" the media is not appendable "


###########
How can I do to fix the first problem ???
I it's not possible, how can i do to fix the second ? :)
###########

Thanks

PS: I think that is a known problem (but i found nothing in the 
archive), so I did'nt put all the information.

If you need more:
http://bergamote.gnux.info/tmp/dvd+rw_overwrite_problem