The security policy can be edited by any XML-aware editor, of which there are a wide variety available, many of which are free. These will allow the generation and editing of a compliant XML policy.
Some tools, such as Altova Authentic, another free tool, provide a flexible, custom, interface for editing parts of an XML document.
A simple, example, SPIF editor built with the Authentic plug-in, is available here. (This currently only shows the simple editing of classification values.)
A command line tool, spx2a, allows the conversion between an XML SPIF to an ASN.1 SPIF and vice versa. The supported ASN.1 include SDN.801 and X.841, with SDN.801-style security categories.
It is expected that the XML SPIF will be the master version of the SPIF, with ASN.1 versions being generated being generated for publication. The tool currently generates a new XML SPIF document when converting from ASN.1 and so any additional information about the policy will have to be manually incorporated.
Future versions of spx2a will include merging of the ASN.1 SPIF into a master XML SPIF document, as will as SPIF signing
Other XML schemas already exist for describing SPIFs and XML Stylesheets provide a mechanism to map between the schemas. Stylesheets exist to map the new XML schema to the schema used by VisualSPIF.