Defining a generic font for a font family that is exported into EPUB2 css files

When exporting a file to epub2, and checking that resulting file using epubcheck, font family definitions in the css file that do not have a generic font family defined are flagged as errors. Those errors will cause an upload of that epub2 file to be rejected by various ebook vendors.

This seems to be only the case for fonts involved in font definitions for spans.

I know how to work around the problem, which is to edit the file manually and add the appropriate generic font family name. For example:

As Generated

.span13 {
background-color: transparent;
color: #000000;
font-family: ‘Times New Roman’;
font-size: 10.0000pt;
font-style: normal;
font-variant: normal;
font-weight: normal;
text-decoration: blink;
text-transform: none;
}

As Modified

.span13 {
background-color: transparent;
color: #000000;
font-family: ‘Times New Roman’, serif;
font-size: 10.0000pt;
font-style: normal;
font-variant: normal;
font-weight: normal;
text-decoration: blink;
text-transform: none;
}

Is there something I am failing to do, or is this a problem in the export generated?

Thank you for your time.

John