Resource types

I thought I'd try asking the excellent Moodle community about this even though it is probably only indirectly related to Moodle but we are seeing students having issues downloading files from Moodle under the following conditions:

OS: Mac OS 10.6 "Snow Leopard"
Browser: Either Firefox or Safari
Connection: Offsite ( a slower connection than LAN speed)

Basically, any Macbooks with Snow Leopard on them have trouble downloading files (through a resources module) that are greater than 1MB if they are offsite no matter what browser they use (if they are on Campus the files come through just fine). What happens is the download starts and then gets to 1MB and just stops (stalls out). No error, no nothing. You can try to resume, etc and the same thing happens over and over again. When I look in the Apache access logs I see a successful hit on the file.php URL (200) and exactly 1MB of data sent (almost like the browser sent an ACK command saying they were done). I've checked into all of our time-out settings and nothing seems very low (in fact, the downloads hit 1MB and stop pretty quickly before a time-out could possibly be triggered it seems). The other oddity is that they can go to a non-Moodle section of our portal with a file download repository (just straight URLs, no fancy send_file calls or chunking) during the same session and those files will download flawlessly. So, it seems like it is some combo of how Moodle does file downloading and how Snow Leopard receives files.
Any help would be appreciated as I have found nothing on the subject and the number of students who can't access files offsite is mounting.

The specs:
Moodle 1.9.3+ is running on Windows 2003 with MySQL 5.0.21, Apache 2.0.58 and PHP 5.2.3
The site is running as pure SSL and we have all files forced to download (we've had display problems in Safari and Firefox with some embedded file types).

thanks in advance for any help or leads
Steve