you are wrong, the same entry with different urls will only be shown as 1 entry in the foobar playlist, those urls will be added as ref1, ref2, etc. in the properties dialog.
you see 2 entries there is because the asx contains 2 entries, and each of those contains only 1 url.
and for manual editing of asx playlist (customising your own playlist), the current behavior is preferable.
The example asx looks like this:
<entry>
<DURATION VALUE="24:00:00" /> <!-- 24 h -->
<ref href="mms://a1367.l672223084.c6722.g.lm.akamaistream.net/D/1367/6722/v0001/reflector:23084" />
</entry>
<entry>
<DURATION VALUE="24:00:00" /> <!-- 24 h -->
<ref href="mms://a623.l672223087.c6722.g.lm.akamaistream.net/D/623/6722/v0001/reflector:23087" />
</entry>
When you say "the same entry with different urls will only be shown as 1 entry in the foobar playlist": So what you are describing would look like this?
<entry>
<DURATION VALUE="24:00:00" /> <!-- 24 h -->
<ref href="mms://a1367.l672223084.c6722.g.lm.akamaistream.net/D/1367/6722/v0001/reflector:23084" />
<ref href="mms://a623.l672223087.c6722.g.lm.akamaistream.net/D/623/6722/v0001/reflector:23087" />
</entry>