Document based Email Templates

Hello Everyone,

I have created few document based email templates in the C4C system.

I want to use them when i am responding to ticket via email.

I also checked on the help document and it is mentioned as we can't use it in the email response.

Can anybody please tell me whether it can be achieve using SDK or with any other enhancements? I would like to achieve this,  as this is the crucial requirement for one our customers.

Thanks in advance.

Nikhil W