Steps taken so far:

1) Created a new custom field for SD incidents:

2) Created a new incident so that it gets the new custom field and verified its existence by looking at the customfields column in SSMS (it's the last one and it has my default value):

3) Made a new xml file to test this for my test role so I don't mess up any active employees.  (I verified I'm using the new xml by purposefully causing errors and seeing them bomb in the browser).  Here is the new tab I added after the General tab:

4) Verified the role has access to the new custom field; it's marked as 'Editable' in the role properties.

5) Opened the incident, selected the tab, and it's blank:

I finally got it to a point where it stopped giving me errors about the custom field (apparently MultiLineString is case sensitive).  There appears to ne nothing I can do to get it to draw the textbox.  There was a point, among my many edits, where it showed up on the first tab below the other custom fields (like it's normally supposed to), but now I can't even get it to show up there.  I read that there are certain section names that do auto-placement of custom fields (secFields, colFields1, and colFields2).  I removed those names, which should have made all of the custom fields appear and need to be manually placed.  That did absolutely nothing.

Anyone ever add tabs with custom fields and able to lend a hand?  My ultimate goal is to have a SQL procedure update the value, so the user won't be editing it ever.  I've done this before with another single line custom field, but the same procedure I used last time to get it to appear isn't working this time.