[web2py] SQLFORM.grid and query

[JmiXIII]

Hello,

I have something like:

    selection=FORM(TABLE(TR(
                TD('Début',INPUT(_name='Deb'),
_class="date", requires = IS_DATE(error_message=T('Doit être de la forme 
AAAA-MM-JJ !'))),
                TD('Fin',INPUT(_name='Fin',_class="date", requires = 
IS_DATE(error_message=T('Doit être de la forme AAAA-MM-JJ !')))),
                
TD('Famille',SELECT('Frappe','Reprise','Tri',_name='Famille')),
                TD(INPUT(_type='submit',_value='Sélectionner'))
                )))
    Deb=request.vars.Deb
    Fin=request.vars.Fin
    Famille=request.vars.Famille
    Ct=0
    query1=db.Rebuts.Date>=Deb
    query2=db.Rebuts.Date<=Fin
    query3=db.Rebuts.Famille==Famille
    if Famille=='Tri' : 
query3=(db.Rebuts.Machine=='TRI')&(db.Rebuts.Famille=='NQ')
    if Famille=='Reprise' : 
query3=(db.Rebuts.Famille!='NQ')&(db.Rebuts.Famille!='Frappe')
    query=query1&query2&query3
    records=db(query).select()
    for record in records:
        Ct=Ct+record.CtReb
    if selection.accepts(request.vars,keepvalues=True):
        pass
    form=SQLFORM.grid(query)
    return dict(selection=selection,Ct=Ct,form=form


Everything is all right except, I can't paginate with sqlform.grid 
(selection form data seems to be lost).
Can somebody give a way to solve it ?
Thanks in advance