custom bb-code

Hello,

I want to add custom bb-codes like this:

[mybbcode]myurltext[/mybbcode]

should be converted to <img class="open_custom_dialog" src=".....?myurltext"/> and in the other way: from html="<img class="open_custom_dialog" src=".....?myurltext"/>" to "[mybbcode]myurltext[/mybbcode]"

I wrote this for an ealier version of ckeditor some time ago per regex. But the new Version has it own BB-Code-Parser an this plugin is more than a simple regex-replace. But my old version overwrite the dataprocessor and isn't compatible to the current version of ckeditor.

And of course I read the documentation and used google.
Is there somebody who can help?