I would agree with @Malcolm
if you see at the following standard code in AX
SysEmailBatch(class) >> sendToBatch (method)
//around line number24, 25, 26, 27
if (attachmentFileNameList)
{
enumerator = attachmentFileNameList.getEnumerator();
while (enumerator.moveNext())
it is taking values from list. so you can pass multiple values, by loop and those multiple values(FileName+Path) will be set to attachmentFileNameList.
that's all, and remaining it would manage itself
