The 167.7 sec limitation is caused by dividing 100 kHz by 2^24. So all you have to do is use two counters instead of one. Use the first counter to generate a pulse train slower than 100kHz and you can use the second counter to generate a very slow pulse train if you set its source to the out of the previous counter. You will have to use the pulse specs on the second counter, because it is going to be used to divide down the initial pulse train.
I hope this helps.
Joshua
