[imp] IMP 3->4 : how to import database?

[helen]

Hello!

I'm trying out the Horde/IMP installation: horde-3.1.3 + imp-h3-4.1.3 + 
turba-h3-2.1.3 which will eventually replace our old installation:
horde-2.2.7 + imp-3.2.6 + turba-1.2.2.

I'm not able to find out how to import the user preferences database 
from the old installation to the new one. It seems to be possible for 
turba (to copy the turba_objects table and add new fields with the turba 
update scripts) but not for imp : the database in the old installation 
has tables imp_addr and imp_pref which don't exist in the new 
installation (the corresponding data seems to be contained in 
horde_prefs which has a different format). The imp package doesn't 
contain any upgrade scripts in the "scripts" directory; the horde 
package has upgrade scripts but they don't deal with the imp tables.

Please help???

Thank you,
Helen