my question really is should I add this to the amount of needed start-up capital?
Most definitely! Regardless of whether you plan to self fund your business venture, or look for outside investors, you will need to take this amount of money into consideration. Otherwise, you are doing yourself a disservice. It will be more of a turn off if you don't include this in your required startup capital, because it'll make it look like you have not thought everything through.
Keep in mind, that this possibly can be a turn off for a number of VC's due to the amount of needed capital.
How much money are we talking about here? I think that there is a big misconception that the smaller the dollar amount you request from a VC, the better. However, this is not the case. Don't waste your time trying to get VC funding if you are looking for less than a few million dollars. VC's are looking to invest in fast growth companies, and for fast growth, you need lots and lots of capital. I think you'll be hard pressed to find a VC willing to invest less than 5 million dollars.
If you are looking for something like $10M in investment, the $100K it's going to cost to get an international patent and trademark is negligible, so it won't turn off the VC one bit. If on the other hand, you only need about a $500K investment, I suggest you look for Angel funding instead.