Ok, so to clear things up, this is what happened:
I´ve had a model which used a terrain blending texture (a shader including the dotproduct2 property). Though this model didn´t make any use of specular- and reliefmapping. See the terrain models in the map Warfare for this, they exactly represent this issue. 
But this issue is not model specific. It´s related to the dotproduct2 or the blending property. One more oddity shows up when using these shader properties is that BSP structure then supports reliefmapping but not specularmapping.
So misc_models do support specular and reliefmapping but shaders using a blending technique don´t.
Maybe some of you may try this out and we´ll see whether this behaviour can´t be confirmed?
By the way this is the shader I wrote:
Code:
textures/map_warfare/blends_earth_rock01_sand01
{
    qer_editorimage textures/map_warfare/blends_earth_rock01_sand01.tga
    
    q3map_bounceScale  0.5
    dpoffsetmapping - 9 match8 168
    q3map_lightmapSampleOffset 8
    q3map_nonplanar
    q3map_shadeangle 95
    q3map_alphaMod dotproduct2 ( 0 0 1 )
    {
        map textures/phillipk2x/natural/pk02_rock01.tga // Primary
    }
    {
        map textures/phillipk2x/natural/pk02_sand01.tga // Secondary
        blendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA        
        alphaGen vertex
    }
    {
        map $lightmap
        blendFunc GL_DST_COLOR GL_ZERO
    }
}