Save DC for supernatural abilities

[Mr.Kraken]

From the SRD:

"The saving throw (if any) against a supernatural ability is:

10 + ½ the creature’s HD + the creature’s ability modifier (usually Charisma)."

When the saving throw for the supernatural ability is not specified, which ability modifier should I use? Charisma or can I use the highest spellcasting ability I have? What determines if I should use Charisma or something else?

[Zaq]

If it's not specified, it's CHA. RAW is pretty open-and-shut on that.

If there's a specific reason you want it to be something other than CHA, and it makes sense for it to be something else (for example, if you get the ability from a prestige class that requires you to cast spells, so you're already basing most of your magical power off of another stat), you can make an argument to your GM that it would make more sense to base the save DC off of your normal spellcasting stat. But RAW, if it doesn't specify, it's CHA.

[Mr.Kraken]

In my case, it's related to Touch of Golden Ice. Since I got to use from the exalted feat, it turns into a supernatural ability. I've taken the Serenity feat to switch several of my paladin abilities to Wisdom instead of Cha, and I'm now using Charisma for nothing beyond skills and some passive defensive bonuses (Mystic Wanderer and Battle Dancer bonuses to AC).

Touch of Golden Ice is divine in nature, and all of my divine powers stem from my Wisdom, not my Charisma. Is it reasonable for me to use Wis for its save DC?

[Thurbane]

RAW it would still be off CHA, but it's not too unfair to ask your DM to change it to WIS...