Mapsforge plugin has configuration xml file tag-mapping.xml where is written which OSM elements will be placed into generated *.map file.
See link: //http://code.google.com/p/mapsforge/wiki/GettingStartedMapWriter#Defining_a_Custom_Tag_Mapping_via_XML
In this case you need to add :
See link: //http://code.google.com/p/mapsforge/wiki/GettingStartedMapWriter#Defining_a_Custom_Tag_Mapping_via_XML
In this case you need to add :
Code Select
<osm-tag key="highway" value="motorway_junction" zoom-appear="12" />