InfoPath Dev

I have a task that I want to set due three business dates from today.

Current set up:

 Field 4: (date/time picker w/ time element hidden)

Due date: (Date/time picker w/ date element hidden. This has a rule connected to it that when the date is picked in field 4, it adds 62,800 seconds to set it with a that date & a 5pm due time)

 The above two fields are sitting together so that it looks like a normal due date to the user. 

I now need to default the Field 4 to three business days from today w/o using the now() function because the now() function would mess up my 5pm due time. 

 Also, my form is connected to sharepoint so no coding allowed. Only formulas. *sigh*

The AddSeconds option, was just not working for me. 

If you use the Add Days function instead of the AddSeconds, you can then use the now () option.

Add a now () field with the following formula as a default value - substring-before(now(), "T"),

Then you can use the following to work out business days - http://www.nothingbutsharepoint.com/2012/11/06/sharepoint-validate-business-day-in-infopath-date-picker-aspx/

then you can add some rules to set your DueDate field etc. based on the calculated date filed as per link.

Add a now () field with the following formula as a default value - substring-before(now(), "T"),

Trying to make this part work..... I've tried:

 substring-before(now(), "T")  (tries to fit both the time and date in the same box so all I see is the date and it's got the red verification boarder around it)

substring-before(now(), "T17:00:00") (shows nothing)

substring-before(now(), "17:00:00") (shows nothing)

substring-before(now(), "T"),"17:00:00" (it doesn't like the comma in between the closing parenthesis and the quote-it errors)

 also just tried concat(substring-before(now(), "T"), "17:00:00") and the outcome was 2016-05-0317:00:00 all in one box

 I figured it out. I needed to use that concat(substring-before(now(), "T"), "T17:00:00")