AutoCAD Inventor :: Setting Texture In Render Style Of A Part

I have got troubles with textures in the new Inventor 2013. When I try to programmatically change a texture in a render style of a part (no matter, whether I use an existing render style or create a new one), when I set the texture file name, Inventor throws an exception "Bad argument". In Inventor 2012, it worked. How textures should be set in the new Inventor?

Sample

PartDocument partDoc = ... some initialization
RenderStyle newRenderStyle = partDoc.RenderStyles.Add("newRenderStyle");
newRenderStyle.TextureFilename = newTexFilename;   //this throws an exception bad format, even if the texture is in the Inventor textures directory 
partDoc.ActiveRenderStyle = newRenderStyle;