It can be done. Unfortunately I cannot recall whose idea it is orignally, but it is possible to have multiple droptanks on the same station. Here is what you should do:
Insert the following data under the last weapon station in the a/c's data.ini:
[LeftWingStationWetSilver]
SystemType=WEAPON_STATION
StationID=X
StationGroupID=3
StationType=EXTERNAL
AttachmentPosition=-3.27,-2.62,-0.18
AttachmentAngles=0.0,-5.0,0.0
LoadLimit=1600
AllowedWeaponClass=FT
AttachmentType=USAF
ModelNodeName=
PylonMass=108.41
PylonDragArea=0.06
FuelTankName=TANK450_F105S
ShowFromCockpit=TRUE
[RightWingStationWetSilver]
SystemType=WEAPON_STATION
StationID=X+1
StationGroupID=3
StationType=EXTERNAL
AttachmentPosition=3.27,-2.62,-0.18
AttachmentAngles=0.0,-5.0,0.0
LoadLimit=1600
AllowedWeaponClass=FT
AttachmentType=USAF
ModelNodeName=
PylonMass=108.41
PylonDragArea=0.06
FuelTankName=TANK450_F105S
ShowFromCockpit=TRUE
Check the StationID of the last weapon station and renumber the two StationIDs (marked red) accordingly. The StationGroupIDs should remain unchanged.
Finally find the components that lists the original LeftWingStationWet and RightWingStationWet as systems (should be the inner or the outer wings) and at the bottom of each section add the following lines:
SystemName[XXX]=LeftWingStationWetSilver
and
SystemName[XXX]=RightWingStationWetSilver
The 'XXX' entries should be replaced with the next number in line.
Now you are done. Well, it may seem confusing (sorry, I'm away from home right now, so I cannot be more specific), but I hope it helps.