The -N option (custom defined build structure) allows one to specify the file
type (using %t) in the file name that is saved to disk. This is the file
*type* (e.g. .html) and not the file *extension* (e.g. .php). Is there any way
to include the original file extension in the file name? 

For example, if one has the following two files in the same directory:

SomeFile.html
SomeFile.php

They will get saved in the mirrored structure as:

SomeFile.html
SomeFile-2.html

Instead I rather want to be able to save them as something like:

SomeFile-html.html
SomeFile-php.html

Is this possible?
Thank you.