Please provide more information about your scenario.
WebADI uploads journal thorugh GL interface, I dont think so you can use WebADI to update journals.
WEB ADI is used to upload new journals only not to update the existing journals.
You can make use of data loader but would request you to provide us the more details with the scenario if possible with screenshots.
If i understand: You can't user WEB ADI for update a existent journal in GL.
The WEB ADI is only used to create a new batchs.