Hmmm... I have tried and tried to reverse pick locks with serrated pins with no luck, however serrated pins really aren't that bad to pick pin by pin! They just make some extra clicks.

(Well, they do need practice still)

Definitely give reverse picking a try too! It may work for you and your lock!
Picking pin stacks with both serrated drivers and serrated keypins, using light tension.. lightly tap on the key pins and you will probably hear a few clicks, but when a pin sets, it will feel slightly different. It may not want to go further without added pressure so don't try to force it just yet... whenever the pin feels set, just move on to other pins. I find that if I hold a light and relatively consistent tension I get the best results... The problem is when you push a key pin up too far and the serrations on the key pin come into play, holding the key pin false set... This is where extremely light tension can be you friend as I find that with a really light tension the serrations on the key pins don't hold very well. Which hopefully causes the key pin to drop back below the shear line and maybe even set properly in a manner similar to reverse picking as mentioned by other people. Be careful not to push the pins too far up if the key pins are serrated, until you get into a situation where all the pins feel set but the plug isn't turning yet... then try to push the pins that you feel need to move. Trust your gut, and/or experiment... until you have memorized the lock... This is the technique I use when trying a lock that contains these type of pins for the first time....
Hmmm... Now, what if you have serrated spools!? Arrrgh! Actually, I find locks with plain serrated drivers and serrated keypins harder to pick that locks with spools and serrated keypins.. the only explanation I can think of for this is that there aren't as many prominent landmarks!

plain serrated drivers can be strange because you sometimes glide over a serration. Believe it or not, serrated spools aren't much more difficult than plain spools, just different.. If your tension is light enough you may not notice a difference.. (I may just be used to them or something) With a very light tension the lock tends to click more when a stack properly sets! (Not always so evident when WD-40 is used, though... depends on the lock...)
On a lock with serrated spools and serrated drivers, I find that the method I end up using until I get used to the lock is to try to get the spools to "lock up". tapping on pins and when I hear a click or two I move on to the next one until I end up landing in the middle of a spool.. I consider spools to be "Landmarks" so I know generally where I am at.. (Half way there for that stack!) It helps me to visualize the pins.
Mixing serrated/non-serrated spools and mushrooms is something I haven't seen... I have also not seen a serrated mushroom pin, which could be interesting...
Spraying in some WD-40 as an anti-spool/serration measure does seem to help! If you are having trouble try the WD both wet and dry.. letting it dry seems to dry out the lock cuz WD acts more like a light cleaner and coating then a lube.. Use Tri-Flow or some other silicone spray lube when you want to lubricate properly... Flooding the lock with a little extra lube may help instead of WD, but not too much lube... (You will have to experiment!)
Anyway, my observations about serrated pins are that if you have plain (non-spool/mushroom) serrated driver pins and serrated keypins then it is harder to tell which serrations you are stuck on, but if the lock has spools (serrated or not) then you can catch on a spool and the serrations on the keypins become less important for that stack because the spools tell you that you haven't gone too far!... Mix and match a bit, add mushrooms, etc.. and you are in for some real fun!
Note: I hear that some brinks locks are using American brand cylinders, so they may even have some spools with serrations. Great fun! The shrouded padlock may be one of these.. The housekey versions that I have seen use a keyway that a kwikset blank fits into.. Don't let that fool you into thinking they are too easy though!
Oh! I tension the top of the keyway lately with some small homemade wrenches... I actually have to use a screwdriver to carefully turn the cylinder when I think it is ready to pop open!
Wow, what a mouthful... I hope there is something useful up above for someone!

I am always interested in hearing about new techniques.. The wierder the better.
Unfortunately, I learned about spools the hard way. Picking at random..

I still come across a lot that I can't pick right away... Time for more practice!
