Yes it did! Kicking myself for forgetting that option, it's better anyway as the iGo has a nice holder mechanism for the phone which is better (holds it higher) with the keyboard open.
So, I opened my Text input settings, turned off auto-capitilaization which is an annoyance if I'm actually touch-typeing which I'm now (!) doing with the iGo keyboard and also turned off the "Use virtial keyboard" which I never use anyway, and returned to typing... and all my special keys were gone! Nothing but lower and upper case letters, space, arrow keys. No numbers, quote, dash, underscore, etc. I went to the Ext Keyboard settings, they were still set to 105 Int'l, US, so I selected Tools-(re)connect keyboard, and save: everything is all right again.
So this works!!! When I am done confirming a reliable shutdown-reconnect sequence I'll turn it over to my wife, who has dozens of contacts to re-enter after I had to re-flash her phone because it entered a perpetual-reboot condition after un-installing BlessN900 in attempting to make the camera work again. (Yes, we didn't backup even using the enhanced kernel. First such trouble since getting the phones and doing everything to them since May).
And it just went away again. All good now. It's hard to reproduce but I'll try if it will help.
... One thing I've been able to repeat: changing Text Input settings seems to wipe the iGo key mappings. After doing that, repeating the Ext Kbd Tools-(re) Connect HID keyboard and Save gets them back.