Modify the system\ds9.ini file. Find the line "LocalMap=title.dsm" and replace title with any map name below:

M01_KiraL1A.dsm
M01_KiraL2.dsm
M01_KiraL1B.dsm
M01_SiskoL1B.dsm
M01_SiskoL1A.dsm
M01_WorfL1.dsm
M03_KiraL2.dsm
M03_KiraL1B.dsm
M03_KiraL1A.dsm
M03_SiskoL2.dsm
M03_SiskoL1A.dsm
M03_SiskoL1B.dsm
M03_WorfL2.dsm
M03_WorfL1.dsm
M04_KiraL1.dsm
M04_SiskoL1.dsm
M04_WorfL1b.dsm
M04_WorfL1a.dsm
M05_KiraL1.dsm
M05_SiskoL1b.dsm
M05_SiskoL2.dsm
M05_Siskol1a.dsm
M05_WorfL1.dsm
M05_WorfL2.dsm
M06_SiskoL1B.dsm
M06_SiskoL1A.dsm
M06_SiskoL1C.dsm
M06_WorfL1B.dsm
M06_WorfL1A.dsm
M06_WorfL1C.dsm
M07_KiraL2.dsm
M07_KiraL1.dsm
M07_SiskoL1A.dsm
M07_SiskoL3A.dsm
M07_SiskoL1B.dsm
M07_SiskoL2.dsm
M07_SiskoL3B.dsm
M07_WorfL3.dsm
M07_WorfL2B.dsm
M07_WorfL2A.dsm
M07_WorfL1.dsm
M10_KiraL2.dsm
M10_KiraL1B.dsm
M10_SiskoL2.dsm
M10_SiskoL1B.dsm
M10_SiskoL1A.dsm
M10_WorfL2.dsm
M10_WorfL1B.dsm
M10_WorfL1A.dsm
M11_KiraL1.dsm
M11_SiskoL1a.dsm
M11_SiskoL1b.dsm
M11_WorfL1.dsm
TrainingRoom.dsm
Entry.dsm
DS9_Ops.dsm
DS9_Promenade.dsm

The following are not level maps but are cinematic cutscenes which are rendered with the ingame engine.

CM01a_SW.dsm
CM01b_SW.dsm
CM04_Lab.dsm
CM05_Kira.dsm
CM06_SW_Capture.dsm
CM10_KiraL1A.dsm
CM10_SWK_L3.dsm
Cm11B_SWK.dsm
CM11_LabRitual.dsm
CM_ArdPrison.dsm
CM_Defiant.dsm
CM_Endcredits.dsm
CM_GlobalSpace.dsm
CM_SpaceStation.dsm
CM_Worf_Endgame.dsm
GCM11end_WraithObk.dsm

After you've saved the DS9.ini file and started up the game, the map that you replaced title.dsm with will automatically load, bypassing the main menu. Once the level is loaded, all you have to do is hit ESC to access the main menu again.