I assume you don't have any TMs to use?
As you know, the female cannot pass down moves in Gen 4 and you cannot breed Pokemon of the same sex, so the parents you currently have won't help. You need a bigger breeding chain.
Theoretically, it would be possible to construct a breeding chain involving one Pokemon that learns Iron Tail via level up, another that learns Shadow Ball via level up, and possibly several other Pokemon that can inherit the moves through TM compatibility and act as a "bridge" to the Field group, which is compatible with Eevee. (That is, you need a sequence of Pokemon compatible with Iron Tail and Shadow Ball via TM that also have multiple egg groups that can eventually link up to Field.) This must involve one continuous lineage of male Pokemon, as any alternative would involve breeding moves onto a female that cannot pass them down.
Unfortunately, this is where you hit a snag. For the breeding chain to work, you firstly need at least one of the following things:
- a Pokemon that learns Iron Tail through level-up that can also inherit Shadow Ball through TM compatibility, thus keeping the chain going.
- a Pokemon that learns Shadow Ball through level-up that can also inherit Iron Tail through TM compatibility.
- a Pokemon that learns both Shadow Ball and Iron Tail via level up.
Unfortunately, there is no Pokemon satisfying any of those conditions in Gen 4, which means chain breeding will not allow you to get the Eevee that you want. (Neither Shadow Ball nor Iron Tail is a tutor move in Gen 4, either, so that is also not an option.)
There are two alternatives to chain breeding, but neither is particularly easy.
- TM30 (Shadow Ball) can be purchased from the Battle Frontier for 64 BP. You could grind for a bit and then teach Shadow Ball to an Eevee that way. (You could also teach Iron Tail, but there's no repeatable way to get its TM.)
- Eevee is in the same egg group as Smeargle. If you were to sketch Shadow Ball and Iron Tail onto a male Smeargle then breed it with a female Eevee, the offspring Eevee would have both moves you want.
To make the Smeargle option work, get Smeargle into an in-game double battle with an ally that knows Shadow Ball or Iron Tail. You can then target your ally with Sketch to get the move you want. To make this easy, make sure Smeargle is slower than your ally, and both your Pokemon are faster than the opponent/s.
You can trigger a double battle using Pokegear rematches. Young Couple Tim & Sue on Route 13 on Fridays or Twins Kay & Tia on Route 15 on Saturdays would do.