change the current record in a detail form

[Marius]

I made a proof of concept for a LightningV4 application (4D18.6) in which employees can register their time and activities for every year of the week (one record per weeknumber/employee/year). I made a detail form in which they can register this, with a toolbar in which they can switch from one week to another. The toolbar has 'next' and 'previous' buttons to switch to another weekrecord. The buttons fire a callback method which queries the new weekrecord.

At first I hoped/expected that the detail form would automatically change its current record after the callback method, but it doesn't. Then I tried to 'refresh' the detail form by sending an $nError:=Ltg_Form_Display for this Table/detailform, which also doesn't work. 

I tried Ltg_Rec_SetCurrent ($TWFchangeID) to switch to another record, but obviously I am missing a point.

Somebody who can help me out? Thanks in advance,

Marius