email logo at another easysocial theme

This is a follow-up question to http://stackideas.com/forums/how-to-change-the-logo-in-email-that-sent-to-user

I do not want to change the logo.png at the wireframe theme directly.
I'm afraid if I upgrade easysocial someday, the new version may override my custom logo.

I try to create a new Easysocial theme and make it default, and then do the following changes. However it fails.

Now I list the steps below, may you suggest me what I missed?

1) Create a new folder "mytheme" at components/com_easysocial/themes

2) Copy the following folders from components/com_easysocial/themes/wireframe/ to components/com_easysocial/themes/mytheme/
a) config
b) images
c) styles
3) Make changes at components/com_easysocial/themes/mytheme/template.json on fields: name, element, desc..etc.
4) upload my logo.png to components/com_easysocial/themes/mytheme/images/emails/logo.png
5) copy the file components/com_easysocial/themes/wireframe/emails/html/template.html to components/com_easysocial/themes/mytheme/emails/html/template.html
6) edit the file components/com_easysocial/themes/mytheme/emails/html/template.html. At line 18, change
From: <img src="http://solo32/components/com_easysocial/themes/wireframe/images/emails/logo.png" />
To : <img src="http://solo32/components/com_easysocial/themes/mytheme/images/emails/logo.png" />
7) make the theme "mytheme" default.

However, the above procedure does not work. Pls advise me the correct steps.

Many thanks.

Seth