In Rusty Hearts, how do I get the "A Simple Task" mission to complete the "All I Want for Christmas is Sewers" achievement?

Apparently, the achievement has something to do with the B3 Sewer level, which is the very first level in the game. This is the achievement's description:

Complete the quest "A Simple Task" from Technical Officer Ryan.

Problem is: I know where Technical Officer Ryan is, but he doesn't have any quests for me!

I've already completed B3 on every difficulty setting, so it seems that I need to accept this mission before I can complete it.

Is there something I have to get/do/achieve before he'll offer me the Simple Task mission?

First, make sure you have the latest update of the game installed.

This video has a walkthrough from the beginning of character creation through getting the achievement:

A Video on YouTube

You must complete level B3 on "very hard" difficulty. The video shows this and it looks like it does indeed work. If Technical Officer Ryan isn't offering you this quest, make sure that you've completed the Militia quest that Georg has for you.

I've followed the video and was able to get the achievement to pop.