To Activate the Outlook Add-in and make the ‘SendSMS’ button visible you may need to do one of the following:

Enable the IntelliSMS Toolbar
1) In Outlook, go to Tools -> Customize…
2) Select the ‘Toolbars’ tab.
3) Ensure that ‘IntelliSMS’ is checked.
4) Click the ‘Close’ button

Enable the Outlook Plug-in
1) In Outlook, go to Tools -> Options
2) Select the 'Other' tab
3) Click the 'Advanced Options...' button
4) Click the 'COM Add-ins...' button
5) Select the checkbox next to 'Outlook Addin'
6) Click the 'OK' button
7) Click the 'OK' button
8) Click the 'OK' button

If the ‘Outlook Addin’ is not visible in the 'COM Add-ins...' list, you can add it manually:
1) In Outlook, go to Tools -> Options
2) Select the 'Other' tab
3) Click the 'Advanced Options...' button
4) Click the 'COM Add-ins...' button
5) Click ‘Add..’
6) Select file ‘C:\Program Files\IntelliSoftware\IntelliSMSOutlookAddin\IntelliSMSOutlookAddin.dll’
7) Click the 'OK' button
8) Click the 'OK' button
9) Click the 'OK' button
10) Click the 'OK' button

Thank you for your feedback, we are currently working on version 2.0 which will hopefully solve this issue.