Capitalisation of "I" in Mail

I have read several messages on the Forum on how to do this and I have gone to System Preferences-Language & Text-Text and have added the required substitution of "I" for a typed single "i".

It works perfectly in Text Editor but NOT in Mail!

Help Please.

According to a comment to this article:
How to use Mac OS X's text substitution - Jimmy Obomsawin, Mac Support

... you have to enable text substitutions in Mail, and indeed in any app, first. This is done in:
Edit > Substitutions > Text Replacement

Thanks for your reply, but as you can see the attached screen shot - all the options are GREYED out.

Is there a step I've missed?

Thanks

Open a new mail first - you have to be at a place where you can put text.

But, it will not work for "i".
Tried it last night - the text replacement requires a minimum of 2 letters.

All this seems to me to be a lot more work than pressing the shift key for an "I".

Here's another solution -- learn to spell.