FSX Roads and rivers not showing

I have been out of scenery desgin for many months and am grabbing my projects again.

I started "reworking" the city of Medellín, Colombia (big one) and used FSX KML to draw the Medellin River which doesn't show in FSX, I also added several main arteries (avenues).

Everything compiled fine and I put it in the appropriate scenery folder (I haven't forgotten that ;-) but when I fly around I don't see any of my roads (polylines) or even my river (polyline).

All smaller avenues I put in one KML folder and tagged the KML FOLDER (rather than each separate polyline) with Roads_Concrete_10_Lanes_Divided_Median. The larger ones I put in another KML FOLDER and tagged the folder with Roads_Concrete_6_Lanes_Divided_Median. The river polyline I tagged with Stream_Lines_Perennial.

Would they superimpose on the city polygons that already appear in FSX? or do I have to first erase the city and do the lines and then fill the holes with mini city polygons?

There is also a large hill that is nearly flattened in FSX but I don't know how to make it higher.