Product code for Steam Association?

[WolfSpirit]

I noticed that in my Steam its advertising DDO now. I've been trying to get my existing DDO account associated with Steam for possible Trophies and other cool things Steam does, including organizing my games. The only way Ive been able to get it is the "Non-Steam Game" way and that simply puts it as a launch icon within Steam and nothing else.
Ive had other "Old" Games that I was able to associate using the "Product Code" I was able to locate on the actual Retail box.
I'm wondering where my "Product Code" is for either my Orginal DDO account or even the Underdark Expansion code I got a bit ago when I bought that?
Failing these, is there any other way to get it properly associated in Steam without downloading the "Fresh" copy or even making a new account?
No WAY Ill be doing a New account!
Thanks for any information!

[Carpe_Noctem]

If you download the game through Steam, you can log in through that client with the same information you use to log in with the non-Steam client.

[LinmorLorendil]

Easiest way i found to get DDO and Lotro included in my steam library:

• download the base game(s) through steam
• Copy your current version of the game over the version that steam downloaded.
  
• All your settings should still be intact, and you will be all patched up.

Although, one thing i didn't like about having those games included in steam, when you attempt to buy points, Steam requires you to add funds to your Steam wallet, instead of just using a card or paypal directly.