Garmin Nuvi 2415: Showing different kind of POIs together on the map

I downloaded and installed Mkgmap-r2494 and compiled my osm data. Then installed it using MapSource but when using it on my Garmin Nuvi 2415 it doesn't show that many POIs while on Driving mode. I always have to search to find nearby POIs or even to see what's is near me while driving. What is the solution, is it from the Mkgmap and/or my Garmin device?

EDIT:

What we see

Even with the standard Garmin maps, the Nuvi 2415 does not seem to have the function to display the POI symbols all together on the map. What is possible is to filter by a POI type and then those POIs are shown as dots:

What we want

But we would like to show different (all) kinds of POIs at once. This is for example possible on the Nuvi 205 series. You click on the map and see all POIs (in high zoom levels)

Map Detail is already set to "more" (that's the max level).

Without that function the device is pretty useless for mapping. To problem is that we have lots of those devices as no others are available in the country and exchanging them is currently not possible.

Is that possible maybe possible with custom TYP files?

EDIT2:

I was able to use Computerteddys TYP file (teddy.typ). Using that I get custom POI icons, but still only when I click the small dots. Still the POIs are not displayed without search or click.