I get the same. I think sourceforge has stopped allowing hotlinking. Use this direct download link: Plugin Manager 1.5.3 .This is what happens when I try to download Plugin Manager:
Unless the siding is only partway up the wall you can just use the outside with a siding texture. A baseboard adds thickness to the wall that you might not like.I will experiment with using a 'baseboard' on the exterior then. It is very tedious and it requires me to make adjustments to the walls because some of them are not appearing in the 3D model even though I'm looking directly at them in 2D.
The only reason I can think of why a siding/baseboard doesn't show in 3D is because there's another wall covering it. That is one of the effects you can get with creating walls that span more than one level, you loose oversight over what wall is on the level and what wall extends from a lower level.
Make sure your email address is correct and check the setting about how often you want notifications. With one notification a day you might get it tomorrow.It says I'm watching this thread, but I still don't get any notifications. I even logged into the website of my email account to check the spam and junk folders and settings, but there is nothing from SH3D in them.