Rabi, for more background, the vddk header file describing the api has the following comment under the ConnectEx call:
# @param transportModes [in] An optional list of transport modes that
# can be used for this connection, separated by
# colons. If NULL is specified, VixDiskLib's default
# setting of "file:san:hotadd:nbd" is used. If a disk is
# opened through this connection, VixDiskLib will start
# with the first entry of the list and attempt to use
# this transport mode to gain access to the virtual
# disk. If this does not work, the next item in the list
# will be used until either the disk was successfully
# opened or the end of the list is reached.
My assumption is that the Connect call works the same way that ConnectEx works with a NULL transportModes parameter.