Custom Image Button Field Type not showing in Sharepoint 2010 List View

Question

I have created a Custom "Image Button" field type and the image button is visible in New,Edit,Display forms, but the I'm unable to see the button in List View. Please help!!. I think i have problem with my fld_xxx.xml and fld_xxx.xsl.

fld_xxx.xml

 <?xml version="1.0" encoding="utf-8" ?>
 <FieldTypes>
<FieldType>
<Field Name="TypeName">Test Button</Field>
<Field Name="ParentType">URL</Field>
<Field Name="TypeDisplayName">Test</Field>
<Field Name="TypeShortDescription">File to Documentum</Field>
<Field Name="UserCreatable">TRUE</Field>
<Field Name="FieldTypeClass">Core.DocumentumIntegration.TestButtonField,
 $SharePoint.Project.AssemblyFullName$
</Field>

fld_xxx.xsl

  <?xml version="1.0" encoding="utf-8"?>
   <xsl:stylesheet xmlns:x="http://www.w3.org/2001/XMLSchema"
        xmlns:d="http://schemas.microsoft.com/sharepoint/dsp"
        version="1.0"
        exclude-result-prefixes="xsl msxsl ddwrt"
        xmlns:ddwrt="http://schemas.microsoft.com/WebParts/v2/DataView/runtime"
        xmlns:asp="http://schemas.microsoft.com/ASPNET/20"
        xmlns:__designer="http://schemas.microsoft.com/WebParts/v2/DataView/designer"
        xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
        xmlns:msxsl="urn:schemas-microsoft-com:xslt"
        xmlns:SharePoint="Microsoft.SharePoint.WebControls"
        xmlns:ddwrt2="urn:frontpage:internal">
        <xsl:template match="FieldRef[@Name = 'Test Button']"
        mode="URL_body</xsl:template ></xsl:stylesheet>