I see what is going on. Your lexical entry is haruanga babuna which is mapped to pasilanga babuna. The capitalization of the first word gets retained but not the second. FLExTrans' transfer engine can't handle this so you will have to do a post-synthesis change.
In the case of Sipsipka going to Sipsip xa, since this gets produced by a rule you could wrap the literal string you are outputting with the 'get-case-from' element. It would look like this:

This means if the original word coming in is uppercase, the xa will come out in uppercase. Likewise if it is lowercase, it will come out in lowercase.
But, you may have other words in a section title that are coming out lowercase for various reasons. So you may want a general solution to make all the words title case.
There isn't a one-line regular expression that would do this. So I see two possible solutions:
1) Add a custom module to your Drafting set of modules that would run some Python code to capitalize all words in a section header.
2) Add a regular expression for each letter of the alphabet. This is not so nice to have 26 expressions in your Text Out rules, but it works.
The expression for 'a' would be Search For: (^\\s.*?\b)a(\w*) Replace with: \1A\2
To make it easy to add all these, you can add the following xml lines below <SearchReplaceRules> in the file Output\fixup_synthesis_rules.xml:
<SearchReplaceRule RegEx="yes" Inactive="no" Comment="">
<SearchString>(^\\s.*?\b)a(\w*)</SearchString>
<ReplaceString>\1A\2</ReplaceString>
</SearchReplaceRule>
<SearchReplaceRule RegEx="yes" Inactive="no" Comment="">
<SearchString>(^\\s.*?\b)b(\w*)</SearchString>
<ReplaceString>\1B\2</ReplaceString>
</SearchReplaceRule>
<SearchReplaceRule RegEx="yes" Inactive="no" Comment="">
<SearchString>(^\\s.*?\b)c(\w*)</SearchString>
<ReplaceString>\1C\2</ReplaceString>
</SearchReplaceRule>
<SearchReplaceRule RegEx="yes" Inactive="no" Comment="">
<SearchString>(^\\s.*?\b)d(\w*)</SearchString>
<ReplaceString>\1D\2</ReplaceString>
</SearchReplaceRule>
<SearchReplaceRule RegEx="yes" Inactive="no" Comment="">
<SearchString>(^\\s.*?\b)e(\w*)</SearchString>
<ReplaceString>\1E\2</ReplaceString>
</SearchReplaceRule>
<SearchReplaceRule RegEx="yes" Inactive="no" Comment="">
<SearchString>(^\\s.*?\b)f(\w*)</SearchString>
<ReplaceString>\1F\2</ReplaceString>
</SearchReplaceRule>
<SearchReplaceRule RegEx="yes" Inactive="no" Comment="">
<SearchString>(^\\s.*?\b)g(\w*)</SearchString>
<ReplaceString>\1G\2</ReplaceString>
</SearchReplaceRule>
etc.