I need to have a tie between two attacca movements. How do I do this?
Use L.V. ties (from the Properties panel) for both the notes at the end of the first movement, and notes at the beginning of the next movement. For the second movement you’ll need to drag them behind the note(s) in Engrave mode. Note that you can speed up this process by doing one manually, then copying the offsets in the Properties panel (manually) to the other L.V. ties (by multi-selecting them and then editing all their properties simultaneously). Alternatively, you can fix one, then copy the note itself to all of the other staves, then repitch accordingly.
It won’t let me drag the l.v. tie. Also, the tie continues for several more measures, so I don’t think it would be a good idea to have an l.v. tie from several bars later offset to appear at the beginning of the flow, as any small change could ruin this alignment.
You need to be in Engrave mode. Select the tie, and it will display handles that you can drag (Alt-drag is best).
I was trying to find a way to move the entire l.v. tie at once. I’ll try that, but I don’t think that the solution would be the best for this situation, since the ties would be from several bars later.
I think you may not be understanding Leo’s advice. Dragging the LV tie “backwards” just means flipping it horizontally. It’s still attached to be note.
Select the note at the beginning of the 2nd movement, add an LV, switch to Engrave, click on the last handle and Alt-drag it to the left until the LV tie extends to the left of the note.
Or maybe I’m the one who isn’t understanding what you’re asking for.
I think that what the OP means is that when first note of a flow is tied to other notes after it, adding an l.v. tie will place it at the end, which might be several bars later. Moving the l.v. tie back several bars can give pretty random results if the layout changes at all. I tried removing the tie, adding the l.v. tie and then adding the tie again, but the l.v. tie just jumps back to the end of the note.
P.S. If you change the shape of an l.v. tie on the first note of a flow and then tie that note to the second note of the flow, the changes you made to the l.v. tie will be applied to the ‘normal’ tie and a new, default l.v. tie will be added at the end of the second note.
If you’d mentioned that the notes at the start of the second movement had continuing (further) ties, I would have elaborated further, but you didn’t, so I didn’t. Other people seem to have chimed in with the right answers 
Sorry, Leo, but FWIW the OP did say in his second post that ‘the tie continues for several more measures’.
Yes, and that was after my post.
True! But the upshot of all this is that it’s not really possible to do what the OP wants, or is it?
It’s possible. Just double up the first note of the second flow, in a different voice, like so:
The blue voice is tied into the next bar; the red voice has an LV tie.
Then grab the red notes and set their Voice Column Index property (in Engrave mode) to 0. You’ll need to do this in the parts separately.
End result:
I’m sure you can do something prettier with the LV ties than I’ve done, but this is just a trivial example.
Clever!