[horde] compression PECL lzf installed but Horde does'nt detect it

[Bruno Costacurta]

Hello,

I installed PECL lzf (for compression and Horde optimizations) but  
test.php does'nt detect it.

1) installation :

PECL install lzf
pecl/lzf is already installed and is the same as the released version 1.5.2

echo "extension=lzf.so" | /usr/bin/tee /etc/php5/conf.d/lzf.ini
question : is this command enough ?

2) test it under Horde :
but test.php from Horde installation does'nt detect it :

...
LZF Compression Support (PECL extension): *No*
If the lzf PECL module is available, Horde can compress some cached  
data in your session to make your session size smaller
...

Thanks for clue or help.
Bye,
Bruno