Howdy.  I'm kind of new to modding, but I managed to add in a few details to this particualr aircraft model (F-19), allowing it to carry external weapons on wingtip pylons.  It's not that realistic, but it seems to work just fine.  I do have a few problems though, but I'll work on those.  I used the following code: 
  
[LeftOuterWingStation] 
SystemType=WEAPON_STATION 
StationID=3 
StationGroupID=3 
StationType=EXTERNAL 
AttachmentPosition=-4.7,-4.30,-0.700 
AttachmentAngles=0.0,0.0,30.0 
LoadLimit=1134 
AllowedWeaponClass=2IR,IRM 
AttachmentType=NATO,USN,USAF 
ModelNodeName=Pylon_LO 
PylonMass=127.2 
PylonDragArea=0.04 
  
[RightOuterWingStation] 
SystemType=WEAPON_STATION 
StationID=4 
StationGroupID=3 
StationType=EXTERNAL 
AttachmentPosition= 4.7,-4.30,-0.700 
AttachmentAngles=0.0,0.0,-30.0 
LoadLimit=1134 
AllowedWeaponClass=2IR,IRM 
AttachmentType=NATO,USN,USAF 
ModelNodeName=Pylon_RO 
PylonMass=127.2 
PylonDragArea=0.04 
  
and added it to the f-19_data.ini file in the weapons stations section.  I also changed the radar to allow for 160 mile scan range and 80 mile track range, and replaced the outdated RWR f-18 model with the RWR from the F-23, which I also downloaded, simply by swapping out the two image files and changing the setting in the f-19 avionics to match. 
  
In order to get the outer pylons to work, I also added them as components in the right/left outer wing modelling, simply by inputting: 
SystemName[004]=RightOuterWingStation in the Right Outer Wing portion of the airframe details and the same thing (with necessary substitution of Left) in the Left Outer Wing station. 
  
If anyone out there has a better way to do what I've done, please let me know.