Yes the form is reader extended to allow web services call ... But i've found a "solution"
I changed my webservice to make a direct query in the LiveCycle database, this way it is faster.
I've got a question though :
When I use the findUser operation, it took like 90 seconds to retrieve the corresponding users as an xml list.
When I use a direct Query multiple row (I wrote the sql request myself), it took like 5 secondes to retrieve the corresponding users as an xml list (with the same informations)
Why is the findUser operation so slow ? What does it do behind ?