I found this so I'm not sure it will work but it's worth a try:
You can send a Gmail to your Google Number and have it appear as a GV SMS text message.
1) Go to GV settings > Voicemail & SMS tab : enable Forward SMS messages to my email (must be a Gmail address) > Save Send a text message from your mobile phone to your Google number.
2) Go to your gmail address that was in your settings above > open the gmail > click on Show Details > copy the long gmail address that ends in @txt.voice.google.com > add it to your Gmail contacts for yourself.
- You can either reply to this gmail message or send a new gmail to this odd looking address. However, You cannot send it from another email provider (e.g. yahoo) at this time. Note: When you reply or send gmail to your Google number, anything in the subject line will not appear in your GV sms text message, and a line in the body of the message cannot be broken with a new line space or by typing enter for a new paragraph.
3) Go to GV settings > Voicemail & SMS tab : enable Forward SMS messages to my email (must be a Gmail address) > Save
4) Send a text message from your mobile phone to your Google number.
5) Go to your gmail address that was in your settings above > open the gmail > click on Show Details > copy the long gmail address that ends in @txt.voice.google.com > add it to your Gmail contacts for yourself.
- You can either reply to this gmail message or send a new gmail to this odd looking address. However, You cannot send it from another email provider (e.g. yahoo) at this time.
Note: When you reply or send gmail to your Google number, anything in the subject line will not appear in your GV sms text message, and a line in the body of the message cannot be broken with a new line space or by typing enter for a new paragraph.