I recently learned that the European version of the Metropolitan (which is called the MR) uses standard international cartridges/converters instead of the Pilot proprietary ones. The Pelikan converter would fit one of those pens.Why would she use a Pelikan converter? I'd stick with either a cartridge or the original Pilot squeeze converter. Make sure that the cartridge or converter is firmly seated in the pen. It should be pretty tight. If it continues to leak, there may be something damaged...a crack or hole that allows air into the pen.