Ext.data.Store : Add a new configuration to proxy Store

Hi ,

I tried to create a new instance of a class 'Toto.data.Store' which have a proxy , my problem is to add a new configuration to proxy ... that's my code :

Code:

var newStore = Ext.create('Toto.data.Store',{
       storeId : 'toto',
       autoLoad : true ,
       proxy : Ext.applyIf(this.proxy , { extraParams : { titi : 20} , 
        pageParam: undefined,        startParam: undefined,
        limitParam: undefined})
});

but I don't see any modification in my store.

Thanks for help.