Yes, that's one of the bugs that not having baldur.exe will cause. (the other one being that a number of opcodes won't be displayed correctly; try seeing a weapon proficiency effect in a .cre in Tutu for an example: fields will be listed as unknown, rather than with the proper type). Mac users will also have to create dummy .exe.
For those code inclined, here's how games are detected:
currentGame = ID_UNKNOWNGAME;
if (new File(rootDir, "torment.exe").exists())
currentGame = ID_TORMENT;
else if (new File(rootDir, "idmain.exe").exists())
currentGame = ID_ICEWIND;
else if (new File(rootDir, "iwd2.exe").exists())
currentGame = ID_ICEWIND2;
else if (new File(rootDir, "nwn.exe").exists())
currentGame = ID_NWN;
else if (new File(rootDir, "swkotor.exe").exists())
currentGame = ID_KOTOR;
else if (new File(rootDir, "swkotor2.exe").exists())
currentGame = ID_KOTOR2;
else if (new File(rootDir, "baldur.exe").exists() && new File(rootDir, "BGConfig.exe").exists())
currentGame = ID_BG2;
else if (new File(rootDir, "baldur.exe").exists() && new File(rootDir, "Config.exe").exists())
currentGame = ID_BG1;
else if (new File(rootDir, "bg1tutu.exe").exists())
currentGame = ID_TUTU;
else if (new File(rootDir, "baldur.exe").exists() && new File(rootDir, "chitin.ini").exists())
currentGame = ID_DEMO;
keyfile = new Keyfile(file, currentGame);
factory = this;
try {
loadResources();
// Expansion pack detection
if (currentGame == ID_ICEWIND && resourceExists("HOWDRAG.MVE"))
currentGame = ID_ICEWINDHOW;
// Detect Trials of the Luremaster
if (currentGame == ID_BG2 && resourceExists("SARADUSH.MVE"))
currentGame = ID_BG2TOB;
if (currentGame == ID_BG1 && resourceExists("DURLAG.MVE"))
currentGame = ID_BG1TOTSC;
Your goal is to have your game detected as ID_BG2TOB (or, if SoA only, as ID_BG2), rather than as ID_UNKNOWN or as ID_TUTU.