Question about roll and crawl.

I developing a title's importer plug-in for Premiere Pro CS6.
I have a question about roll and crawl of Premiere Pro SDK.

1.A function to acquire the duration of the clip in the timeline.
  I want to set for the user in the time line on the duration of the roll(and crawl).
  I hope for a method same as the duration setting of the roll(and crawl) which I made by a standard title in Premiere Pro CS6.

2.Is imImageInfoRec.isRollCrawl supported?
  It has been set to 1 imImageInfoRec.isRollCrawl but, selector of imRollCrawlRenderPage and imGetRollCrawlInfo is not called.

3.About a value of inFrameTime of imGetSourceVideo when I set imImageInfoRec.noDuration = imNoDurationStillDefault.
  Because I wanted to do duration setting without a limit about roll(and crawl), I set imImageInfoRec.noDuration = imNoDurationStillDefault.
  However, inFrameTime of imSourceVideoRec receiving in imGetSourceVideo becomes the unidentified value.
  In this case, please teach a handling of inFrameTime value.

Thank you.