The problem is not the "--xtx switch", but the lack of support for the
underlying (xdvipdfmx) driver.
Sorry, please remember I'm very far from there...
I was just meaning: the problem is in xetex engine?
I googled a bit and found the following slides:
see page 18 in particular.
thanks, means really nothing to me :-)
In spec-fdf there is:
\definespecial \doattachfile {\doPDFattachfile}
\def\doPDFattachfile#1#2#3#4#5#6#7#8%
{\bgroup % title width height color symbol file
\edefconvertedargument\PDFfile{#8}%
% beware: the symbol may (indirectly) use the file
% reference when typesetting the object number;
\presetPDFsymbolappearance{#5}{#6}{#2}{#3}{#4}% sets width/height
\startPDFsymbolappearance
\doPDFembedfile\PDFfile{#7}{#8}%
\doPDFgetembeddedfilereference\PDFfile\PDFobjectreference
\setFDFlayer\@@DriverAttachmentLayer
\doPDFannotation{\width}{\totalheight}
{/Subtype /FileAttachment
/FS \PDFobjectreference\space
/Contents (#1)
\PDFsymbol
\FDFlayer
\PDFattributes}%
\stopPDFsymbolappearance
\egroup}
Something similar needs to be added to spec-dpx.tex.
Can't follow you here. What is spec-dpx?
Best
-a-
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