How to make a genderless Pokemon have a gender and vice versa

[wildvine47]

I'm attempting to set up an Egglocke for a friend, and a group of us are creating eggs for it. However, we'd like to be able to set genders for certain Pokemon that don't normally have genders, such as Magnemite or Staryu. I can get a Magnemite to display as female in PKHeX via Batch Editor, but then when I go to load the save file in Black 1, the Magnemite does not display as female in-game, and presumably will not function as one in game with regards to Attract and the like. How exactly do I go about getting this to work?