Based on feedback from users we have made the automated acknowledgement SMS optional for the Forward to Email action. This means that people wont be told that their message has been forwarded to your email address but tt also means that you wont pay for those auto acknowledgements!
The easiest way for you to reply to these SMS2Email type messages is to use Bulletin Messenger. Simply subscribe and get your email address validated by our support team and then you can start to have a two way conversation with a cellphone from your email.
Also in this wee update for the Forward to Email action is the option to have the email sent as plain text to reduce the likelihood that it gets marked as spam.

The Forward to REST action got a little love as well and now allows you to define a SMS reply from mQuery. This brings it in line with the other actions and is a good addition as it allows you to setup a REST endpoint that doesn't necessarily need to send a SMS now (e.g. it just collects data).
For people that want to respond with what their server returns in response to the SMS, consider using the SMS an Extract of a Web Page action.

If you have any questions or comments please contact us. We look forward to hearing from you.