There are a few ways to do this depending on how you are getting the sequence files. If you are calling the GetSequenceFileEx method, you can just pass the GetSeqFile_FindFile (0x20) flag in the SequenceFileFlags property. If you are using the ApplicationMgr.OpenSequenceFile method, this is automatically done for you.
If you want to use the FindFile function in general, you can use the Engine.FindFile method.
Allen P.
NI