clarification re: dates for rights issue

Just wondering if someone could better explain the wording in todays announcement re: letters sent to holders.

13 May 2013 per the timetable (next mon) is listed as the date for which CD's commence trading wtihout the entitlement to participate in the rights issue.

My understanding is therefore today (friday) is the last time you can buy or sell in and out of SUM to trade your eligibility for the rights issue. Following this on monday 13th you could sell out and still participate in the raising?

The question then is how does the 'record date' come into play. As it's referred to in the letter consistently as to determine eligible holders the cutoff is 5pm WST on 17 May 2013.

So which is it? Can i sell out on the 13th and use the proceeds to fund partly taking up of my rights? Or must we still be on hand as at 17 May? Sorry just abit confused re: wording on the docs as my understanding was the ex-date governs.