Yes, this does indeed seem to be a limitation with respect to the PHP DOM library. Much easier to fix on the Inkscape side. Choose to save as "optimized svg"
And then make sure the "style to XML" box is ticked.
As explained in this post you can use Scribus with Inkscape to prepare press ready pdf file.
Scribus is another free, gratis, open source & cross platform program.
The steps are basically:
Find out the colour profile that your printing service uses, download and install it.
Set Scribus to use the same colour profile
Load the svg file, needs to be ...
There is no reason why you can not use SolidWorks or say Autocad for this. Its not often done but possible. I use Maya and Creo all the time to make logos in 2D, i just export the logo in EPS and be done (Ok so the NURBS surfaces must be turned to Beziers, no big deal in many cubic and quadratic cases).
The thing is constraints solvers are not terribly time ...