HOWTO embed all fonts into PDF

I got an error message from IEEE PDF eXpress (http://www.pdf-express.org/) with my manuscript pdf file.
It said 'Font Times-Roman, Times-BoldItalic, Times-Bold is not embedded' in error report.

From googling, I have found a solution.
The reason is that the ghostscript doesnt embed some standard fonts into pdf.
I guess the programmer thought every system have that fonts, so it is useless to embed such standard fonts into pdf.
However, IEEE requires all fonts to be embedded.

the solution is ..
modifying /usr/share/ghostscript/8.61/lib/gs_pdfwr.ps (ubuntu 8.04 hardy heron) as follows:

/.standardfonts [
/Courier /Courier-Bold /Courier-Oblique /Courier-BoldOblique
/Helvetica /Helvetica-Bold /Helvetica-Oblique /Helvetica-BoldOblique
/Times-Roman /Times-Bold /Times-Italic /Times-BoldItalic
/Symbol /ZapfDingbats
] readonly def

to

/.standardfonts [
% /Courier /Courier-Bold /Courier-Oblique /Courier-BoldOblique
% /Helvetica /Helvetica-Bold /Helvetica-Oblique /Helvetica-BoldOblique
% /Times-Roman /Times-Bold /Times-Italic /Times-BoldItalic
% /Symbol /ZapfDingbats
] readonly def

reference: http://osdir.com/ml/editors.lyx.general/2004-06/msg00124.html