Passing value to FieldCustomContent

How can I pass value to custom content?

Here is what I am trying:

panel.AddField("", “some_field”, db.Varchar, form.Custom).FieldCustomContent(template.HTML(<input type="text" name="some_field" id="some_field" value='{{ .Value }}'>)).

But this does not work. {{ .Value }} is not parsed and it is shown as it is.