How can we allow users to view invoice distributions in Preview mode when they are using the AP Invo

We are loading invoices using the AP Open Interface tables.  We do not want to validate the invoices until they are approved.  We want our approvers to be able to log into Oracle using the Invoice inquiry menu (AP_APXINWKB_VIEW_MENU) to review the accounting before they approve the invoice but when they click on the Distributions button the distributions form is empty.   We can see the distributions in Preview Mode (distribution class of Preview) using the Invoice update menu (AP_APXINWKB_MENU).  But we do not want to give these users update access to the invoice workbench.  Please advise.  Any help would be