How to compile mysql with ut8?

[Richard]

Hello everyone,
I'm new to this list, so I hope that this is the right one for this 
question.

My system runs on Debian sarge with Apache2 and mysql-server-5.0 
installed with apt-get, the mysql package comming from the dotdeb backdoor.

My server is going to host a forum that is actually on a server with 
mysql set to utf8. On my server all was left to default settings, which 
is latin1 in my case.

On the server where the forum is at the moment I have only got access 
with phpmyadmin and if I ask phpmyadmin to convert (with iconv) it gives 
off errors about illegal characters.
So the only solution was to change mysql to utf8 which I did and the 
restauration of the phpmyadmin dump of the forum's database was a success.

To change mysql to utf8 I added the following lines to my.cnf :
under  [mysqld]
default-character-set=utf8
and under [client]
default-character-set=utf8

However I have got proftpd and postfix which both need to be able to 
connect to mysql and in my syslog I get this :

Character set 'utf8' is not a compiled character set and is not 
specified in the '/usr/share/mysql/charsets/Index' file

It's true that I do not have a utf8 file in /usr/share/mysql/charsets/

So now I have to somehow compile mysql with UTF8.

I have set my system locales to utf8 and tried reinstalling mysql : 
apt-get install mysql-server-5.0 but this does not help.
With mysql set to latin1 all works fine as latin1 is included in 
/usr/share/mysql/charsets/

So my question is how can I do this ?

Thanks in advance !