qlandkarteGT always shows red dots with the housenumber when there is such a point, but my Garmin shows the point only sometimes / seldom.
Question 1: Why?
Question 2: Is there a way to change this behaviour?
Question 3: Is it possible to create a rule in lines-options like “if there is any point in the line with addr:housenumber add the housenumber to the polyline”?
I think 0x0209 is not supported by Garmin.
See http://wiki.openstreetmap.org/wiki/OSM_Map_On_Garmin/POI_Types to check which poi types you can use. For addresses I’ve used 0x2900 and I recommend to use a TYP file so you can render it the way you like.
If there is a point on the line with any addr: tag, mkgmap will render it as poi so you dont have to specify it in the lines style.