I just did the timing belt on my 01 V70 T5 today. I too couldn'nt find a destinctive mark. The mark is forward (toward front of car) of the notches for the belt, and will translate to a "groove" in the pully. This will in turn align with a part on the block that has 2 "protuburences". The correct alignment is on the left. If you have the 2 cams in alignment, then the crank is also aligned. Make your own mark to ensure nothing moves while doing the job as extra insurance. I counted the nubs between the notches on the cam to make sure I had the tension correct when putting on the new one. Getting the dampener off was the challenge, I ended up modifing a steering wheel puller to make it work. I also found it quite challanging getting the belt on. I found that positioning the belt over all the pullies and then putting on the tensioner last worked best for me. Only engage a few threads to allow the tensioner to align correctly after getting it started. HOld the adjuster steady with the 6mm allen wrench while tightening the attachment bolt once you have the proper tensioning. Flex the belt a few times to make sure the tensioner is working. My mechanic suggested a couple of seconds of run time prior to deciding if the tension is correct. I did, and was just fine.

I wish you the best of luck.

Jerry
01 V70 T5