I tried doing that just now and it still isn't working. As it was running it showed it had scanned more pages than it had added to the sitemap for example:
Links depth: 2
Current page: products/17_AAG-1128-49.html
Pages added to sitemap: 391
Pages scanned: 836 (24,501.0 KB)
Pages left: 2733 (+ 595 queued for the next depth level)
Time passed: 0:16:08
Time left: 0:52:46
Memory usage: 4,804.5 Kb
In the end it has skipped 1000 pages every time I have run it, crawled 4164, and only indexed 431.