请给个思路？

[雨谦飞扬]

有一文件（文本），里面有若干段（见下面）
%BeginFont
Handler:WinTTHandler
FontType:TrueType
FontName:SimSun
FamilyName:SimSun
StyleName:Regular
WeightClass:400
WidthClass:5
AngleClass:0
FullName:宋体
FamilyNameNative:SimSun
StyleNameNative:Regular
FullNameNative:宋体
WritingScript:SimplifiedChinese
WinName:宋体
FileLength:10500332
%EndFont

现在需要把每一段的FamilyName的内容和FamilyNameNative的内容修改成FullNameNative的内容，即把SimSun修改为宋体，修改完成的见下：

%BeginFont
Handler:WinTTHandler
FontType:TrueType
FontName:SimSun
FamilyName:宋体
StyleName:Regular
WeightClass:400
WidthClass:5
AngleClass:0
FullName:宋体
FamilyNameNative:宋体
StyleNameNative:Regular
FullNameNative:宋体
WritingScript:SimplifiedChinese
WinName:宋体
FileLength:10500332
%EndFont

每次都用手工修改，非常麻烦，请问用VB如何实现自动智能修改？能给个详细的编程思路吗？谢谢！