WMS Maps and Transparency

[chbla]

Hi there,

First of all, I'm aware of:
http://help.locusmap.eu/topic/wms-tiles-as-overlay
http://help.locusmap.eu/topic/transparency_of_wms_layers

However, I've got the following WMS Service:
http://vogis.cnv.at/mapserver/mapserv?map=i_hoehen_und_gelaende_r_wms.map&version=1.3.0&service=wms&request=getcapabilities

The Layer "Tourenkarte Neigung" is meant as a slope gradient map for ski touring in my area (see screenshot below)
The problem with it is that it of course is meant (and only makes sense as) an overlay, not an individual map.

And my question is: How can I make use of it?

Is the provider to blame that they do not support transparency? However, if they would, wouldn't this be a fixed opacity setting which is rather useless?
In QuoVadis and other mapping apps I can use any map I want as overlay, and select the opacity and transparency color myself. I think this would make a lot of sense in such a scenario..

Or is there another way?

Edit: Tried in Oruxmaps, seems it is working there

[jusc]

1. You should load p. e. a vector map of the region or a raster map
2. load WMS map with  opacity 33%

[chbla]

Haha, how could I miss that.. sorry
Alright then it works the same was as in Orux, that's fine

The only thing that would be useful (also in this example) would be a color that could be specified
as 100% transparent as many overlay maps I saw have a white background :/
The blending modes are not necessary in my opinion