I ran into a similar situation recently while printing from Linux. I think it depends on the PPD file they are using. They may need to modify the PPD file to show the available output bins and then in their linux print command, they would need to use -o OutputBin=Top option. I found the following PPD options in another driver, which may help. I think it can be copied into an existing PPD, that is being used by the printer.
*OpenUI *OutputBin/Output Destination: PickOne
*OrderDependency: 20.0 AnySetup *OutputBin
*DefaultOutputBin: Auto
*OutputBin Auto/Automatically Select: ""
*OutputBin Middle/Center Tray - Lower: "
currentpagedevice /OutputAttributes get dup 0 known
{0 get dup null eq
{ pop }
{ dup length dict copy
setpagedevice
} ifelse }
{pop}
ifelse
"
*End
*OutputBin Middle2/Center Tray - Upper: "
currentpagedevice /OutputAttributes get dup 1 known
{1 get dup null eq
{ pop }
{ dup length dict copy
setpagedevice
} ifelse }
{pop}
ifelse
"
*End
*OutputBin Top/Left Top Tray: "
currentpagedevice /OutputAttributes get dup 2 known
{2 get dup null eq
{ pop }
{ dup length dict copy
setpagedevice
} ifelse }
{pop}
ifelse
"
*End
*OutputBin Stacker/Finisher Tray: "
currentpagedevice /OutputAttributes get dup 30 known
{30 get dup null eq
{ pop }
{ dup length dict copy
setpagedevice
} ifelse }
{pop}
ifelse
"
*End
*CloseUI: *OutputBin
