appeng.api.parts.IPartItem
This is a pretty basic requirement, once you implement the interface, and createPartFromItemStack you must register your bus with the Bus renderer, using AEApi.instance().partHelper().setItemBusRenderer( this ); then simply add these two methods, which tell MC to use the Block Textures, and call AE's Bus Placement Code.
@Override
@SideOnly(Side.CLIENT)
public int getSpriteNumber(){ return 0; }
@Override public boolean onItemUse(ItemStack is, EntityPlayer player, World world, int x, int y, int z, int side, float hitX, float hitY, float hitZ) { return AEApi.instance().partHelper().placeBus( is, x, y, z, side, player, world ); }