If you use Nero:

Click new to make a new compilation and choose CD (not DVD).
Then, below there is a list:
CD-rom
Audio-CD
CD (Mixed)
CD Extra
Copy of CD
Video-CD
Super Video CD
miniDVD
CD-rom (bootable)
CD-rom (UDF)
CD-rom (UDF/ISO)
Audio book CD

Choose miniDVD here, the rest is the same as with regular DVD burning.