you need to make it available by editing your DefaultLoadOut.txt file.
go to C:\Program Files\Activision\SFC 3\Specs
find the DefaultLoadOut.txt, right click on it and select Properties in the pop up menu, make sure Read Only is not checked, click OK
open the DefaultLoadOut.txt file with notepad
in Notepad, look at the menu bar at the top, click on Format and make sure that Word Wrap is unchecked.
next click on edit in the menu bar, click on Find.. in the box that pops up, type in Scimitar
click OK.. Scimitar will be highlighted on your page.. look to the right and you will find the letters NS...
Very Carefully, but your curser behind the S and press backspace 2 times...
save the file and close notepad.
Scimitar is now available in Single Player and Skirmish game modes...
Good Luck... Scimitar was designed for the Nemisis add on mission only, thus the ship was set for NS or Non Selectable.. meaning neiter you nor the AI could use it.. now AI and you can buy it with NS removed...
Hope that this helps.