AA weapons in SH maps?

[Gen Cobra]

I just started a map that is a tower. I set up a munitions room in the basement. I filled it with every weapon in the game. When i launch the map in spearhead I get aa weapons but i can use spearhead weapons only if i pick them up. Why am i starting with aa weapons? Do I need to specify that the map is a spearhead map? And how do I do that? How do i get the spearhead weapons when i start a tdm instead of aa weapons.