Changing my Apple ID Account query

Question

I have an apple ID that is not in the form of an e-mail address.  For example: abcdefghijk99.  I've had it for years, going back to when I was a Windows PC user (until I saw the light 2 years ago and switched to Apple products) for itunes purchases initially.  As far as I was concerned my appleid was fine and I've used it to purchase more music and apps for my Mac, iphone, ipad and ipod since.  Then I discovered a problem. Having downloaded the Find My iphone app it prompted me for an appleid in the form of an e-mail address and would not accept my original appleid.  Likewise the same issue applied to the the same for finding the ipad.
So I checked it out online a little to try and see if it is possible to change your applid and found the "My Apple ID" section at https://appleid.apple.com/cgi-bin/WebObjects/MyAppleId.woa/ and that under the "Manage my account" section you can make changes to your appleid account.  But changing your name to an e-mail address is not one of them, at least if it is to the e-mail address that is your default e-mail address as held by itunes.
So ok, and I imagine others would suggest this, that I could set up another ID as an e-mail address and use this for the Find my iphone and ipad facilities.
But looking forward, it doesn't solve the problem at all.
1.  I've built up a fair history of purchases using itunes and from the App store under my original non e-mail address and I don't want to lose them.  And of course future updates to software that I've purchased from the App Store would be against my original appleid and I don't want to lose that thread.
With the advent of "iCloud" I understand that it will want you to enter your Appleid in order to upload to, sync your devices with etc.,  If it wants this to be entered in e-mail address format then it will not be accessible to me.
2.  Appleid software is inconsistent in that for iTunes and The App Store it will allow the ID to be entered both as a non E-Mail address and as an E-Mail address.  But for the Find my iphone App, will only accept an E-Mail format address as the Appleid.  I think this is perhaps a legacy of MobileMe, which possibly The iCloud is going to use the MobileMe format as an Appleid.  And if so that will have implications for other users who have the same type of appleid as me.
3.  All I want to do is simply change my Appleid to my default E-Mail address, but it won't let me.  I raised this issue on the telephone with Apple who understood my issue, did not immediately know the answer, but said would discuss with colleagues and E-Mail me back.  The reply was:
"I talked about your case with my colleagues. The only suggestion that came to mind is that you consult iTunes via email and ask if they can amend the ID or if it would be possible to transfer you purchases from one account to another account."
Ok. So it led me to here, the Support area, because it seems impossible to be able to raise the issue by E-Mail with them, as much as I've tried to by going from page to page trying to find out "how to contact them".
So does anyone here have any good ideas as to how I solve my problem?   Additionally is there anyone from Apple itself who monitors questions raised in this community?  If so could they let me know that they appreciate my problem and how/if it can be dealt with?
Hoping someone comes up with a solution and looking forward to hearing from anyone with suggestions.

Answer 1

Solved with assistance from iTunes support.  The main problem was that you cannot use an e-mail address which is associated with your existing account.  So the answer is to set set up a new e-mail address with your Internet Service provider.  Next step is to log into iTunes using your existing appleID (which in my case was a non e-mail address as mentioned in my question) and then modify your itunes id and e-mail account, both to the new e-mail address.  I tried it and it worked.  All downloaded history such as itunes music and apps that I have downloaded onto my devices over time has been retained.  Furthermore I can now use the "Find my iPhone app" to find both my iphone and iPad.  Likewise will be able to use this revised appleid to access iCloud once available and synch my apps etc.,  Very pleased with iTunes Support's prompt response and remedy.