Stop trying, and look magnanimous instead:

North Korean leader Kim Jong Il expressed regret about his country’s nuclear test to a Chinese delegation and said Pyongyang would return to international nuclear talks if Washington backs off a campaign to financially isolate the country, South Korean media reported Friday.
...
Kim told the Chinese delegation that "he is sorry about the nuclear test," the newspaper reported.
...
Kim also said that "we have no plans for additional nuclear tests," the Yonhap news agency reported, citing an unnamed diplomatic source in Beijing.

I think this is bigger news than everyone seems to think it is... mostly because an apology tends to mean more in Asian cultures than here in the west.  I think because they've gone to this extreme... of actually apologizing... it means that they're extremely overconfident that a second test would be successful when their first shows all signs of failing miserably.

So now they're trying to act magnanimous, and saying that they're willing to come to the table.  But make no mistake about it... had the first test been successful, or there was a decent chance of the second test being successful, then they'd never do this.

They're coming to the table much weaker than they did before.  That is of course if these bilateral/multilateral talks ever end up happening in earnest.

Update 10/24:  The Chinese are now denying the apology ever took place:

North Korean leader Kim Jong Il did not apologize for his regime's nuclear test when a special envoy from China's president visited Pyongyang last week, a Chinese Foreign Ministry spokesman said Tuesday.

South Korean news reports said last week that Kim had expressed regret for the Oct. 9 test during a visit by State Councilor Tang Jiaxuan, who delivered a personal message and a gift from Chinese President Hu Jintao.

"These reports are certainly not accurate," ministry spokesman Liu Jianchao said at a regular press briefing. "We haven't heard any information that Kim Jong Il apologized for the test."

OK... call me overly optimistic about what I said before.  I should have been more skeptical.