Not able to open XMind files from IE in read only mode

I have configured my SharePoint Farm to support .xmind file types

Below are the steps I have done

1.   Added an entry in DOCICON.XML

    <Mapping Key="xmind" Value="xmind_file1.png" EditText="XMind Mapping Software"  OpenControl="SharePoint.OpenDocuments"/>

2. Added an entry in htmltransinfo.xml

    <Mapping Extension="xmind" AcceptHeader="application/vnd.xmind.workbook" HandlerUrl="" ProgId=""/>

3. Added a MiME type 'application/vnd.xmind.workbook' in the Inetmgr.

Now, xmind files are getting detected, but I am not able to open xmind files in read only mode from IE.

Xmind files are working perfectly from Mozilla, but my client wants the xmind to be working perfectly from IE.

Need a help on this issue....