Can I sustain Weapon of the Astral Flame twice and get two attacks with it?

Question

The Sustain Minor portion of Weapon of the Astral Flame's (Cleric Level 1 Daily, Divine Power) text reads "The weapon persists and makes a second­ary attack." Can I spend my minor action and a move action downgraded to a minor action to make this attack twice?

Daily • Conjuration, Divine, Fire, Weapon

Standard Action Melee weapon

Effect: You conjure a weapon of astral flame in your space. The weapon lasts until the end of your next turn. When you move, the weapon moves with you, remaining in your space. The weapon makes the following primary attack when it appears.

Primary Target: One creature

Primary Attack: Strength vs. Reflex Hit: 1 [W] + Strength modifier fire damage, and the primary target takes a -2 penalty to attack rolls until the end of your next turn.

Sustain Minor: The weapon persists and makes a second­ary attack.

Secondary Target: One creature

Secondary Attack: Strength vs. Reflex

Hit: 1 [W] fire damage.

Answer 1

No, because you can't Sustain a power twice in one turn (or round, depending on the book you're using).

From PHB1 p278, look under the header Durations for the list item Sustained Durations. It has this to say:

Starting on the turn after you create an effect, you sustain the effect by taking the indicated action: a standard action, a move action, or a minor action. (You can sustain an effect once per turn.)

That part in brackets is the key. You could interpret this permission as either "you can do it exactly once" or "you can do it at least once", but given the latter is already the assumed default, I recommend that it means the former.

The Rules Compendium makes the restriction more explicit, as well as restricting it to only once per round, preventing you from also sustaining the power on other peoples' turns if you managed to figure out a way. From the section on Sustained Durations on p227:

Limitations: The creature can sustain a particular effect only once per round [among other limitations].

So you can only get one sustain, and one Minor-action attack, out of that power each turn.