How to overwrite adminhtml sales order renderer?

Question

I am a beginner in magento. I needed to add notice to admin for some special product. But I have added my modifications to core files. I added my code to,

app / design / adminhtml / default / default / template / sales / order / view / items / renderer / default.phtml

Cause I was able to access some product attributes there and it was the best place I found.
Now I just would like to use a copy of this in,

app / design / adminhtml / default / my_newtheme /templates/..../default.phtml

and use it in my xml,

app / design / adminhtml / default / my_newtheme /layout/..../sales.phtml

But it does not work....

It is a small change for me , not some huge one that i need special block and some observer or so...or do I?

Answer 1

To override the default package/theme in adminhtml, you have to specify it to magento either in app/etc/local.xml or in a config.xml file of your custom module. Once you did that, your files copied from

app/design/adminhtml/default/default/

to

app/design/adminhtml/my_package/my_theme/

will be processed.

More details in this post.