[Merkaartor] Merge layers or working with shape files

[Etienne Ruedin]

I have a shape files with about 10 000 km of ways. I can import them,  
Merkaartor opens a new layer for them.
Then I add some OSM tags to the points or ways (railway, gauge,  
operator, network, name, source, attribution, description, etc), but  
I cannot upload them.
When I draw a new way (in the layer of the downloaded map probably),  
the way is uploaded when I press ctrl-U… but not was I changed or  
tagged at the imported ways.

the layers: -yellow = Yahoo / grey: ... / blue = Background map from  
OSM I downloaded / blue, red striped: the import from the shape file

* Is there a way to merge two layers?
* Or how to upload the treated ways from the shape file layer to OSM?  
(the layer is blue with red stripes)

When I click on a way with the right hand button of the mose ->  
Features -> Force upload
I can upload the way, but only as untagged way, all the work  
(tagging) I did before remains in Merkaartor and is not uploaded

Has someone any ideas?