When you send a sequence or clip from Final Cut Pro 5 to Soundtrack Pro, some elements, including speed clips, generators, slugs, transitions, and all markers other than scoring markers, are not included. This happens because Final Cut Pro does not render these elements out to the base layer movie which is sent to Soundtrack Pro's Multitrack Editor or Audio Waveform Editor.
Clips that were sent to the Waveform Editor will still have the elements when you open the clip in Final Cut Pro. Clips that were sent to the Multitrack Editor will not have these elements when opened in Final Cut Pro because the original will be replaced with the edited sequence.