[Dami]

Yes & No! I loaded the editor to check this, and realised I've never made a magic weapon for d20. It's not quite as simple as other items, but not hard to work out. Doing it from scratch would take a little more work to make sure you didn't miss anything important. I've made the item for you (attached) and here's how I did it.

In the editor, under Equipment / Weapon, Magic:
Use "New (Copy)" to copy an existing item ("Bow of Songs") and change the name and ID code. Change the weight to that of a longbow. (Assuming MW, removed the Enhancement bonus) Click on "Counts as Weapon" and select Longbow, remove the "Source". Modified "Gizmo" bootstrap to Longbow. Added 1/charge a day and show on Tracked Resources.
I did cost calculations as if its a masterwork weapon, with Quickened Truestrike (1 charge/day) added. A standard Truestrike spell would make it much cheaper, but it would be a standard action to activate the spell-effect.

If your bow is +1, then you can edit the file to set the "Enhancement Bonus" to 1, and increase the cost by 2000gp.
To use - put the user file into your HL/data/d20 folder.