June 2, 2015: Edited to add that opensim 0.8.1 supports Multi-Attachments.
Opensims do not support Multi-Attachments. Boots are best worn when attached to the lower leg, but that means that it is not possible to wear pants with cuffs or pants with normal legs.
As a solution I have started to update my boots, offering a separated ankle boot which can be attached to the foot and worn under cuffs. But one must we aware that only shoes that do not have parts that cover the lower leg will fit correct. Ankle boots attached to the feet will not follow the lower leg movements. The result its that the leg will pinch the ankle when it moves. Therefore these ankle boots can be worn only under pants or cuffs.
But you can make a copy of the ankle boots and attach them to the lower leg. Save it to a folder and wear them with skirts or shorts. So actually you are receiving a pair of kneelong boots plus a pair of ankle boots for the same price.
I am aware that some customers hate resizers. The reason for me to use a resizer it’s because I can make my footwear no modify. Why no modify? Well there are scripts one can insert into a modify item and get an exact copy of the item but under their name. You can argue, that there are copybot viewers. Yes, that’s true. And I answer that you wouldn’t leave your front and backdoor open just because there are criminals who will hit a window anyway. I believe that to have the nerve to log in with a copybot viewer and risk to be caught, it is necessary that the one has no scrupels to steal. While the like-me-and-you user (the mayority) will not log extra with such viewer to steal, but can be tempted to just insert a script and make a copy as the chances to be caught are little. So for now my footwear stays ‘no modify’ and I write it clear on each product so that the customer has the choice to buy or not to buy.
Since March 2013, I’m using an improved resizer. This one is able to reduce the size of the shoe to a very tiny size, making it possible for skiny avatars, for petits or kids avatars to resize the shoes to fit their body.