[galaxy-dev] new data type.

Hi, I created an XML file for a tool. This tool has an Nexus input. When I click the input field of the web interface for this tool, it shows all kinds of data that I can select. How do I restrict the list to show only data in nexus format? I added a line in the registration part and the sniffer part of the datatypes_conf.xml and I also created a class called Nexus which inherits the class galaxy.datatypes.Sequence, but this doesn't solve the problem. Thanks, Luobin