As a BizTalk Developer you always need to add your dlls project to Global Assembly Cashe.
The simplest way to do this procedure is by a command which you need to create it in IDE.
By doing the following procedures:
1-Open VS.NET.
2- In Tool bar click Tools
3- From Tools click External Tools..
4-In External Tools dialog box click Add button.
5-In Title field add title like Install to GAC.
6- In Command field browse a gacutil.exe file which is in
C:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\Bin\gacutil.exe
it depends where you install your visual studio
7-In argument filed add the following /f /i $(TargetPath)
i means install to assembly
f means if dll exsits then overwite it
$(TargetPath) is the path if selected project
8-In initial directory field add $(TargetDir)
$(TargetDir) means directory of the selected project
9- Check Use Output window to inform you in output window the dll has been added to GAC
10- Click Ok button.
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Now your cammand is ready.
Just select the project you want to add it to GAC
then select tools then Install to CAG command you created.
Hope this will Help!