Custom Properties and Equations for use in BOM Tables

We use a set of custom properties in our parts andassemblies(TitleLineOne, TitleLineTwo, and PartNumber).  Iwould like touse these values in the BOM table but am havingtrouble writing anequation in the part/assembly to set my customproperties equal tothe SW pre-defined properties (Description andPart Number,respectively).  I found a post in the forumsindicating that Ishould useDescription = \$PRP:"Property1"\$PRP:"property2" (mine isDescription =\$PRP:"TitleLineOne"\$PRP:"TitleLineTwo") but I get a "The syntax of thisequation isincorrect" pop-up.  I've triedDescription =\$PRP:"TitleLineOne" + \$PRP:"TitleLineTwo"butstill get the syntax error.  The only way I have been abletoget past the syntax error is to useDescription ="TitleLineOne" + "TitleLineTwo" but doingthisgives me the red exclamation point and returns a value of"???" inthe model tree.

Can someone point out what I am doing wrong?

I would also like to know the syntax to generate the SWpre-definedPart Number value for use in the BOM table (somethinglike PartNumber = ...)

Thanks in advance for any help
SolidworksBill Of Materials