in the default tpl you see this code
{.if| %user% |{: {.append| %folder-resource%\hfs.comments.txt |{.filename|%item-resource%.}=uploaded by %user%
/append.} :}/if.}
i can imagine how it should be, but i didn't test it
{.save|%item-resource%.comment|MD5: {.md5 file|%item-resource%.}.}
{.if| %user% |{:{.append|%item-resource%.comment|
uploaded by %user%.}:}/if.}
this version doesn't use hfs.comments.txt