Hello Marcel,
Thank you for contacting National Instruments.
NI does not have a tool that will convert into MDF format. There is a Plug-In for Diadem which allows you to read MDF files at http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=E267F645DF776A21E034080020E74861&p_node=201258 .
The following website might be helpful to you. It has general information on MDF format and tools for creating MDF files. http://www.techquila.com/index.html
I hope this helps,
Sean C.
Applications Engineer
National Instruments