[SWFKit]

You can assign a flag to the Dialog.fileSave method

Dialogs.fileSave([filter[, default_ext[, filename[, flags]]]])

flags Integer. Can be one of the following values

OFN_READONLY 0x00000001
OFN_OVERWRITEPROMPT 0x00000002
OFN_HIDEREADONLY 0x00000004
OFN_NOCHANGEDIR 0x00000008
OFN_SHOWHELP 0x00000010
OFN_ENABLEHOOK 0x00000020
OFN_ENABLETEMPLATE 0x00000040
OFN_ENABLETEMPLATEHANDLE 0x00000080
OFN_NOVALIDATE 0x00000100
OFN_ALLOWMULTISELECT 0x00000200
OFN_EXTENSIONDIFFERENT 0x00000400
OFN_PATHMUSTEXIST 0x00000800
OFN_FILEMUSTEXIST 0x00001000
OFN_CREATEPROMPT 0x00002000
OFN_SHAREAWARE 0x00004000
OFN_NOREADONLYRETURN 0x00008000
OFN_NOTESTFILECREATE 0x00010000
OFN_NONETWORKBUTTON 0x00020000
OFN_NOLONGNAMES 0x00040000
OFN_EXPLORER 0x00080000 // new look commdlg
OFN_NODEREFERENCELINKS 0x00100000
OFN_LONGNAMES 0x00200000 // force long names for 3.x modules
OFN_ENABLEINCLUDENOTIFY 0x00400000 // send include message to callback
OFN_ENABLESIZING 0x00800000

Eg. Dialogs.fileSave("Zip files(*.zip; *.gz)|*.zip; *.gz|Text files(*.txt)|*.txt|All files(*.*)|*.*|", null, null, /*OFN_OVERWRITEPROMPT*/2);