Please refer Integration Server built in services guide esp pub.date and pub.string to build your logic. but I doubt your requirement can be built with out of available services.
Mostly you need to write a java service using java API’s like Calendar/Date and built the logic to extract dates between two string.
Hope others can direct you better, but from my knowledge this is what I feel needs to be done.
You might want to search the download section of the community for a Package called PSUtilities.
This one was developed by Professional Services members and contain a lot of helpful services.
Some of the services there made it into the WmPublic package meanwhile therefore checking the IS Built-In-Services Reference is a good point to start.
Appreciate all your inputs. It helped me solved my problem.
I was able to solve it using flow service.
What I did was…
Calculate days difference of startDate and endDate.
newDate=startDate
REPEAT (count using days difference)
IF
newDate == endDate Do nothing
ELSE
Increment newDate by 1
Append newDate to dateRange(String list)