ive never had problems passing arrays by post, in fact is that not the best way to do it? a simple ISSET test on the array can tell you if anything has been posted.
e.g. this code in a form would be one element of an array.
echo("
<tr><td width=\"17\"><img src=\"images/help.jpg\" title=\"help here\"></td><td width=\"150\">Description</td><td width=\"325\"><textarea rows=\"6\" cols=\"80\" name=\"arraymilestonedetail[mil_description]\" class=textbox wrap>$row01[mil_description]</textarea></td></tr>
");